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Concourse 2

Relative pronoun clauses (aka adjective clauses)

relatives

This is quite a long guide.
If you are here for the first time, the advice is to work through it sequentially but if you are returning to check something, here's a list of the contents to take you to its various sections.
Clicking on -top- at the end of each section will bring you back to this menu.
The graphic summary is here.

Definition Embedding and clause structure Defining vs. non-defining Meaning Pronunciation The five central pronouns
Cases and concord Subject or object? Omitting the pronoun Using that Prepositions Reduced clauses
Nominal / fused clauses Clause position Stacking relative clauses Sentence relative clauses Other languages Teaching relative clauses 

This guide contains a number of tasks for you to do as you go along.  The tasks are designed to make sure you have understood the content.  If you don't want to do them, simply click on the links for the answers and read on.
howl

Definitions

The dog which howled all night

Here's a definition from Parrott who avers that relative clauses are:

complex structures which allow the speaker to express themselves succinctly and fluently
(Parrott, 2000, p. 381)

They actually do rather more than that but it's a good working definition to begin with.

Relative pronoun clauses are usually said to be clauses starting with who(m), that, which, whose defining or identifying the noun they follow.
So, for example, in
    The dog which howled all night and kept me awake belongs to my neighbour
The noun, dog, is rendered unique among millions of dogs because only this one howled and caused a sleepless night.

two ways

Relative pronoun clause vs. adjective clause

In that sentence, the relative clause, which howled all night and kept me awake, is acting to modify the noun, dog, and that makes it adjectival in function.  For this reason, some analyses will refer to these structures as post-nominal adjectival modifiers (Celce-Murcia & Larsen-Freeman, 1999: 571) or adjective clauses (Yule, 1998: 240).
We'll stick with relative pronoun clause here because it is more familiar but those two descriptors are equally valid.  If you prefer to call these structures adjectival clauses, simple replace the terms mentally in what follows.
The key point is that relative pronoun clauses modify and/or identify an already specified noun phrase and in that sense they are akin to adjectival phrases and clauses.

Relative pronoun clauses also vary from other types of post-modifiers of nouns in the level of explicitness they bring to the reference.  For example:
    The man who waited in the queue
is quite specific about the man and identifies him uniquely, but:
    The man waiting in the queue
and
    The man in the queue
are both considerably less explicit about the man and there could be other men in the queue.
The other noteworthy issue is that, because relative clauses are usually finite (insofar as the verb carries markers for tense and person), we can identify with greater specificity when the event or state occurs.  In the three examples above, only the first, with a relative pronoun clause, allows us to set the event in time.  For example:
    The man waiting in the queue will make a complaint
    The man waiting in the queue has made a complaint
    The man in the queue made a complaint
    The man in the queue will have made a complaint
etc. in which the tense form is not marked in the subject of the verb make.
However,
    The man who had been waiting in the queue made a complaint
etc.
sets the waiting in time by its tense form (in this case, past perfect progressive).

The grammatical function of relative pronoun clauses is one of subordination to which there is a guide on this site, linked below in the list of related guides at the end.
That they are subordinate is made clear by their removal from a sentence.  If, for example, we start with:
    That's the car which caused the accident
we cannot remove the relative pronoun and leave two well-formed clauses:
    *That's the car.  Caused the accident.

Some languages, see below, rely on using adjectival expressions alone to do this task, having nothing remotely like the English relative pronoun structures.  For speakers from these language backgrounds, the concepts and meaning are, initially, at least, obscure.

question

What about adverbs?
She told me where to find it  

If you are wondering why where, why, when and how are not in the list above, the answer is that these words are analysed elsewhere in the guide to relative adverbs, linked below.
Relative pronouns, as the name implies, are words which stand for a noun, a gerund, a noun phrase or a nominalised clause (i.e., different sorts of nouns).
If the word refers to why, where, when or how an action is carried out or a state exists, it is an adverb, not a pronoun and does not belong here.
That relative pronouns and relative adverbs appear to be structurally related is not in question but relative adverbs function differently and perform different grammatical tasks.  Relative adverbs cannot, for example, appear as the objects or subjects of verbs (because they aren't nouns of any sort).  One relative adverb, how, cannot refer to a noun at all.

One good reason for keeping the concepts of adverb and pronoun relative clauses separate is that, as we saw above, relative pronoun clauses act syntactically and semantically to subordinate one clause to another.  Relative adverbs clauses, on the other hand, are coordinating and their removal leaves two well-formed clauses which can stand alone.  If, for example, you remove the adverb from:
    That's the house where he got married
you get
    That's the house.  He got married
and, although some sense is lost, the clauses are, nevertheless, potentially independent.

As we shall shortly see, relative pronouns are distinguished by the functions they perform in sentences, technically their relationship to the arguments (most commonly subject, direct object, indirect object etc.).
Understanding how to use them relies on being able to untangle the grammatical functions of phrases and clauses in sentences.

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embed

Embedding and clause structure

Before we can discuss meaning, we need to look at the usual structure of relative pronoun clauses.
If we take two simple sentences such as
    The lucky children came to the party
and
    The children enjoyed themselves
we can make a single complex sentence as:
    The lucky children who came to the party enjoyed themselves
The two simple sentences form what is known as the kernels of the more complex sentence.

How did this happen?
The first thing to do is identify the Head of the subject noun phrase.  In this case, in the first sentence, it is the noun children which happens to be pre-modified by the adjective lucky.  In the second sentence the same noun is not pre-modified by an adjective but in both cases there is a pre-modifying determiner, the.

Following Chomsky, we can make the rules for doing this conversion, like this:

  1. Place the second clause after the first noun phrase in the first sentence (in other words, embed the whole clause within the second clause).
    That gives us:
        The lucky children the children came to the party enjoyed themselves
  2. Now delete the second noun phrase:
        The lucky children the children came to the party enjoyed themselves
  3. Now replace it with the appropriate relative pronoun, in this case who because the reference is to people.
    That then gives us:
        The lucky children who came to the party enjoyed themselves

Later, we shall see how the pronoun can be omitted, too, when we are dealing with the object noun phrase.
The process above may seem quite simple to speakers of languages which use relative pronouns in the way that English does.  However, for those whose first languages do not do so, or who use relative clauses very differently (i.e., most non-Indo-European languages) it is not a simple transformation and taking people carefully through the three steps above can pay dividends.
They will require a good deal of practice at doing this for themselves.  (See below for an idea about how to do this.)

If you prefer a diagram, it looks like this:
embedding

watch To see how this is explained in a lesson for learners, watch this short video.

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liberty ghandi

Defining vs. Non-defining
Restrictive vs. Non-restrictive
Identifying vs. Non-identifying

Again, the terminology varies.  Here, we will use defining and non-defining because the terms are the most familiar but the three pairs of ways to describe the two fundamental types are synonymous.
Here are four sentences to compare:

Before you go on, decide which of those sentences you are happy to accept.

think Task:
What's the difference in meaning between these pairs of sentences?
Click here when you have an answer.
  1. At the first meeting, which was held yesterday, the chair invited comments from everyone.
  2. At the first meeting which was held yesterday the chair invited comments from everyone.
  3. The kids, who came with me, had lunch on the train.
  4. The kids who came with me had lunch on the train.

Now look again at the first four sentences concerning statues and decide what the issue was.  Here's the comment:

Sentence Issue
The Statue of Liberty, which stands in New York, is well known. The clause between the commas is simply adding information concerning the location of something known to us all.
The Statue of Liberty which stands in New York is well known. There is only one such statue so to omit the commas would be wrong.  You cannot define that which is unique.
The statue of Gandhi which stands in Tavistock Square is well known. There are many statues of Gandhi around the world so to define a particular one by where it is, is acceptable.
The statue of Gandhi, which stands in Tavistock Square, is well known. This is also acceptable.  Here we are talking about a statue of Gandhi but adding information to say where it is, not defining it.

think Task:
Try another slightly different example:
In the following, why is it not possible to take out the commas in the first sentence or to insert them in the second?
Click when you have an answer.
  1. The Nile, which runs through Egypt to the Mediterranean, is vital to the country’s prosperity.
  2. The man who asked me to marry him on that memorable evening is still my husband.

Defining (restrictive or identifying) relative pronoun clauses are by far the most common.

question

Wh-questions

When we ask wh-questions, we are forced to use defining clauses because of the nature of the question so, for example, while we can have

  1. The woman, who(m) you met at the party, is his sister
  2. The woman who(m) you met at the party is his sister
  3. The book, which you bought in London, is written by her
  4. The book which you bought in London is written by her

in which sentences a. and c. contain non-defining clauses which just add information to the woman and the book respective and in which sentences b. and d. contain defining relative clauses which tell us which woman and which book in particular is the focus of the sentence.
When we make a question, of course, we are concerned to get a definite answer so the question will contain a defining not a non-defining clause.  We allow, therefore:

  1. Who is the woman you met at the party?
  2. Which is the book you bought in London?
    but not
  3. *Who is the woman, you met at the party?
    or
  4. *Which is the book, you bought in London?

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meaning

Meaning

The difference between restrictive / defining and non-restrictive / non-defining relative clauses is not just a grammatical wrinkle in English because the meaning the speaker / writer conveys differs very significantly depending on which type of clause is used.
The key point is that defining clauses give required information whereas non-defining clauses give additional information.
The distinction is a familiar one concerning given and new information.

For example, in these two sentences, we have a clear distinction in meaning:

  1. The woman, who arrived at the hotel this evening, has gone out
  2. The woman who arrived at the hotel this evening has gone out

In sentence a., both speaker and hearer are aware of the existence of the woman and know to whom reference is being made.  The information about the hotel is new.
In sentence b., this is not the case and the speaker selects the grammar accordingly because the necessary information to distinguish the woman in question is needed for comprehension.  The assumption in sentence b. is that the hearer already knows about the woman and that she arrived at the hotel.  The only new information is that she has gone out.
This is even clearer when we use names rather than common nouns.  Compare, for example:

  1. Margaret, who arrived at the hotel this evening, has gone out
  2. Margaret who arrived at the hotel this evening has gone out

In sentence c., the person referred to is known to both speaker and hearer and the information about the hotel is peripheral but probably new to the hearer (why else state it?).
Sentence d. is very strange and it is difficult to imagine it ever being produced unless there are two Margarets to whom reference may be being made and the speaker needs to disambiguate to refer only to one of them.  In this case, the speaker assumes that the hearer knows there are two possible people called Margaret to whom reference is being made and that one of them arrived at the hotel and one did not.

One way to explain this distinction to learners whose languages may not make any distinction at all between the two types of clause is to consider a simple attributive adjective phrase in a sentence such as:
    The hardworking students passed the examination
which is ambiguous because this may mean either:
    The students who worked hard passed the examination (and other students, less hardworking, did not)
or
    The students, who worked hard, passed the examination (all of them)
and to make it clear what is meant, i.e., to disambiguate the sentence, we have resorted to the use of a defining or non-defining relative clause.
For more on how relative pronoun clauses serve to disambiguate, see the guide to ambiguity, linked below.

It is difficult to signal what is meant by intonation in the adjective phrase, although stressing the adjective strongly might show that a restrictive meaning is intended.  In the written form, no punctuation changes can be made to show what is meant, although one could resort to underlining or other emphasis markers.
The two relative pronoun clauses are much more easily distinguished by intonation and punctuation signals.  See below.

Non-restrictive or non-defining relative clauses are not, naturally, the only way to achieve the effect of post-modifying the noun phrase.  There are two non-finite clause types that can function in the same way:

  1. using an -ing form:
        The manager, checking the accounts, noticed the missing money
    which could be rephrased as:
        The manager, who checked the accounts, noticed the missing money
  2. using a past participle in a passive clause:
        The theft, discovered by the manager, was reported to the police
    which could be rephrased as:
        The theft, which was discovered by the manager, was reported to the police

This kind of post-modification of the noun phrase is generally non-restrictive so the defining or restrictive forms without commas do not provide the same sense:

  1. The manager who checked the accounts noticed the missing money
    Implies that there were other managers who did not check the accounts.
  2. The theft which was discovered by the manager was reported to the police
    Implies that there were other thefts which remained undetected or that other thefts were detected by other people.

By the same token,
    The theft discovered by the manager was reported to the police
without commas or pausing, can imply that there were other thefts, undiscovered by the manager, which remained unreported.
It is not possible to have:
    *The manager checked the accounts noticed the missing money
for reasons to which we will shortly turn.

compress

Compressing the data

The second concern in the field of meaning of relative pronoun clauses is the way in which they can be used to compress information and make communication more efficient.  We could state, for example:

The guest complained.  The guest was in Room 310.  The room is near the air-conditioning fans.  The fans make a noise.  The noise was the problem.

or we can compress the data with relative clauses to produce:

The guest who was in Room 310, which is near the air-conditioning fans, which make a noise, complained about the noise that they made.

which is more efficient, more fluent and altogether more sophisticated in terms of information packaging.  It actually contains four relative clauses, two defining and two non-defining.

eggs

Theme and rheme

The third issue concerning meaning is the way in which relative clauses link themes to rhemes.

If the terms theme and rheme are unfamiliar to you, you can check the guide on this site, linked in the list of related guides at the end.  For now, however, it is enough to explain that the terms refer to how longer pieces of discourse are made coherent and cohesive by the way in which information is linked.
Here's an example, using a relative pronoun clause:

The parents eventually came to collect the children who had been waiting in the rain outside the school.  By then, they were soaked through and thoroughly miserable.

In that short passage, the theme is:

The parents and the rheme is all that follows it:
    eventually came to collect the children.
The rheme then becomes the theme of the next clause, who, which stands for the children and the pronoun has its own rheme:
    had been waiting in the rain outside the school
The next clause reiterates that theme as by then, they which has its own rheme:
    were soaked through and thoroughly miserable.
The fact that they were unhappy will, probably, form the next theme and so on for the rest of the discourse.

All that is relevant here is that one of the common ways that theme-rheme connections are made is via the use of defining relative clauses.  Non-defining relative clauses do not do this as, for example, in:

The boss, who came in early every morning, took the call.  The contact was from the customer in Canada wanting to know where his consignment was.

in which the theme is The boss, who came in early every morning (not just the boss) and the theme is took the call.  As we would expect the call forms the theme of the following part of the discourse with the consignment following on as the next rheme.
The fact that the boss came in early every morning is additional information and part of the first theme.  It does not form part of the rheme or go on to be a theme in itself.

4

The 4 key elements of meaning

If you find this analysis hard going, it does not matter for now.  It is, however, important that you are aware of the fact that relative clauses do four things concerned with meaning:

  1. They can act to restrict the scope of the subject of a clause by defining.
  2. They can act on the subject non-restrictively by merely adding information.
  3. They can make texts cohesive and coherent.
  4. They can compress information to make texts, whether spoken or written, more efficient in communicating ideas.

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question

Next question

think Task:
If you use phrases like all of which, either of whom, both of which, the majority of whom, none of which etc., would you normally expect to separate the clause off with commas or not?  Click here when you have an answer.
pronounce

Pronunciation

Pronunciation issues with relative clauses concern tone groups in particular.

think Task:
In written English, commas are used to distinguish the two types.  How does this work in spoken English?
Click here when you have an answer.
forget

Memory test

write Task:
There are five central relative pronouns in English, listed at the top of this page – what were they?
Click here when you have written them down.

cases

Cases and concord

These are connected issues so we will treat them together here.

suitcase

Case

There are three cases in English grammar which can be distinguished in relative clauses and in other parts of the pronoun system.  We shall see below that the case of the pronoun is important in terms of structure.
Here's a quick reminder of what they are:

subject or nominative case
The nominative case is represented by three relative pronouns:
  1. who: is used to refer to people for the most part, although animals also qualify for its use in certain circumstances and so do groups of people represented by collective nouns.  For example:
        The person who asked the question was happy with the answer
        It wasn't my dog who barked all night
        The committee who considered the case were ill chosen
        The family who booked the holiday cottage failed to arrive
  2. which: is used to refer to objects, places and animals with little personal connections even when gender is clear.  The pronoun may also represent a group of people.  For example:
        Athens, which is the capital city, contains almost half the total population of Greece
        Is she the cow which attacked you?
        The team which won was always favourite
    Rarely, which may refer to people unconnected to the speaker so we may hear, for example:
        The child which came top of the class got a prize
    Any personal connections forbid the use of which so:
        *My child, which came top of the class, got a prize
    is almost certainly not allowable.
  3. that: is an alternative to both who and which and can be used for personal and non-personal reference.  For example:
        The person that asked the question was happy with the answer
        It wasn't my dog that barked all night
        Is she the cow that attacked you?
        The team that won was always favourite
object or accusative case
The accusative is represented by four relative pronouns:
  1. who: is used to refer to people for the most part, although animals also qualify for its use in certain circumstances and so do groups of people represented by collective nouns.  For example:
        The person who I asked knew immediately
        My dog, who I love dearly, is getting very old
        The committee who we asked to consider the case were useless
  2. whom: can only be used in the accusative and is used to refer only to people, or collections of people.  For example:
        Peter, whom I like a lot, can be a difficult person
        The policeman whom I gave the report to didn't seem interested
    It is sometimes averred that whom is only formal, unnecessary and disappearing but it is frequently seen in academic writing and in some circumstances is unavoidable so:
        The man to whom I gave my address is over there
    is acceptable, if formal, but
        *The man to who I gave my address is over there
    is not.
    The pronoun whom is rarer with reference to collectives of people:
        ?The committee whom we asked to consider the matter is useless
  3. which: is used in the same way in the accusative as it appears in the nominative (for places, objects and unconnected animals):
        Athens, to which I flew on Thursday, is my favourite European city
        The newspaper which I bought at the airport was two days old
        That's the cow which he bought last week
        The team which I support won
  4. that: is an also an alternative in the accusative to whom, who and which and can be used for personal and non-personal reference.  For example:
        The person that I asked had no idea
        This is the book that I bought today
possessive or genitive case
The genitive case is only represented by whose.  This pronoun may never be omitted.  There are some issues with it:
  1. The genitive represents more than simple possession and the pronoun whose can be used for four out of five of the types of genitive.  Like this:
    Possession:
        The boy whose case was stolen is waiting outside
    Subjective (referring to the subject):
        That's the man whose reaction was so violent
    Origin:
        My friend, whose email I received today, is coming to visit
    Objective (referring to the object):
        The criminal whose early release caused a controversy is on TV tonight
    However, there is no relative pronoun use for the descriptive genitive so:
        *The hour whose work it is
    is not available to be formed from
        It's an hour's work
  2. The pronoun whose need not refer to people but there is an avoidance issue for most native speakers.  Many are happy to accept, for example:
        The ship, whose captain was asleep, hit a rock
    but less happy with
        The hotel whose rooms are most comfortable is The Grand
    and very dubious of
        ?The house, whose price is £200,000, has been sold
    Avoiding the pronoun in these cases, however, leads to some clumsiness and
        The ship, of which the captain was asleep, hit a rock
        The hotel in which the rooms are most comfortable is The Grand
        The house, the price of which is £200,000, has been sold
    are seen by many speakers to be clumsy and also avoided so the thoughts may be rephrased as:
        The captain of the ship which hit a rock was asleep
        The Grand is the hotel which has the most comfortable rooms
        The price of the house which has been sold is £200,000.
handshake

Concord

Concord refers to the agreement between the noun and the verb and is usually not problematical so we have
    The house which he bought was poorly maintained
    The houses which they bought were poorly maintained
and so on.

There is a small problem with collective nouns, however, because:

  1. When they are represented by which, the verb is usually singular:
        The committee which must decide the issue meets tomorrow
  2. When they are perceived as human and represented by who the preference is a plural verb form:
        The committee who must decide the issue meet tomorrow

We saw above that expressions such as all of which, either of whom, both of which, the majority of whom, none of which etc. occur in non-defining relative pronoun clauses but concord is sometimes an issue.  For example:
    The cake, all of which was eaten, was delicious
    The people, all of whom were asked the same question, were unanimous
    The children, neither of whom takes the bus to work, are usually late.
    The books, none of which ?was / ?were available, would have been most helpful.

Teaching issues connected to concord are discussed below and there is also a link to a guide to the area at the end.

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subject or object

Subject or Object?

It's important to know whether the relative pronoun is acting as the subject or the object of the verb.

think Task:
Is the relative pronoun in the following examples the subject or object of the verb?
Look at the underlined clauses.
Click when you have an answer.
  1. The man who bought the tickets really is just being generous
  2. The tickets, which hopefully will allow us entry, are very welcome
  3. The man that we thanked seemed genuinely surprised
  4. The tickets which he bought were quite expensive
  5. Only the senior doorman, who we gave the tickets to, noticed that they were fakes
simple

Two simple rules

Rule #1:

If the relative pronoun is followed directly by a verb phrase, it’s the subject.

So, in
    The man who just bought the car
the relative pronoun, who, is followed directly by the modified verb phrase, bought.  This means that the relative pronoun stands for the subject of the verb.

Rule #2:

If the pronoun is not followed by a verb phrase (but by a noun phrase or pronoun) it is the object.

So, in
    The book which she bought was a first edition
the relative pronoun, which, is followed by a pronoun, she, so it cannot be the subject of the verb.  The relative pronoun stands for the object of the verb and can be, and routinely is, omitted.

Relative pronouns may also refer to indirect objects (as in 11. above).  For example, we can get from:
    She read the children a story.  The children were delighted.
to
    The children to whom she read a story were delighted.

Because the indirect object can frequently be moved and introduced using to or for (a process called dative shifting) the usual form of such relative clauses follows that of relative pronouns as objects of prepositions (see below).
Other examples are:
    The dinner which he ordered for us was delicious
    The people for whom she cooked dinner were grateful

The relative pronoun may, as it stands for an object, be omitted but when this happens the preposition is often left, so to speak, stranded, and we get:
    The children she read a story to were delighted
    The dinner he ordered for us was delicious
    The people she cooked dinner for were grateful

By its nature, the pronoun whom is usually preferred to who in such formulations because it is an object-case only pronoun.

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gap

Omitting the relative pronoun

Now we have the subject-object distinction clear, we can see why it is important in English to know which grammatical function the pronoun is performing.
In focus here is what as known as the zero or Ø relative pronoun.  The clause structures are unchanged, but the pronoun may, in some circumstances, be omitted.

think Task:
In which of sentences 7 – 11 can you omit the relative pronoun?
Why (not)?
Here they are again:
  1. The man who bought the tickets really is just being generous
  2. The tickets, which hopefully will allow us entry, are very welcome
  3. The man that we thanked seemed genuinely surprised
  4. The tickets which he bought were quite expensive
  5. Only the senior doorman, who we gave the tickets to, noticed that they were fakes
Click here when you have an answer.
meeting

Using that
The man that she met  

Originally, incidentally, the word that was only a singular neuter pronoun with the plural form those and it is still used in that way, of course.  It has, however, been altered by a process known as grammaticalisation into a purely functional word which, in the case of relative clauses, does not carry the sense of plurality so we can have, for example:
    I'd like that hat and those gloves
but the word has been grammaticalised in Modern English and now functions as a relative pronoun in, e.g.:
    The books that I gave her
where it is unmarked for plural or singular and we cannot allow the more logical
    *The books those I gave her.

Here are the example sentences again with some more at the end:

  1. At the first meeting, which was held yesterday, the chair invited comments from everyone.
  2. At the first meeting which was held yesterday the chair invited comments from everyone.
  3. The kids, who came with me, had lunch on the train.
  4. The kids who came with me had lunch on the train.
  5. The Nile, which runs through Egypt to the Mediterranean, is vital to the country’s prosperity.
  6. The man who asked me to marry him on that memorable evening is still my husband.
  7. The man who bought the tickets really is just being generous
  8. The tickets, which hopefully will allow us entry, are very welcome
  9. The man that we thanked seemed genuinely surprised
  10. The tickets which he bought were quite expensive
  11. Only the senior doorman, who we gave the tickets to, noticed that they were fakes
  12. The man whom we met turned out to be his brother.
  13. The man who met us was his brother.
  14. The table which I wanted had been sold.
  15. The table which cost too much was the only one left.
think Task:
In which of these sentences 1 – 15 can that be used as the relative pronoun instead of who(m) or which?
What's the rule?
Click here when you have an answer.
style

Style

Stylistically, as the rule states, relative clauses formed with that as the pronoun are considered less formal and some would avoid the use of the pronoun in formal writing and speech.
There are, however, some points to make here:

  1. The style rule holds when that is used to represent a subject person.  So, for example:
        The guests who arrived late
    is more formal that the synonymous:
        The guests that arrived late.
  2. However, the pronoun that is often preferred to represent the object of the verb, even when it refers to people because some feel uncomfortable with the use of whom or simply want to avoid having to decide whether to use it at all.  So, for example:
        The guests whom he invited
        The guests who he invited
        The guests that he invited
    are all considered acceptable and the second two of equal formality.
    Nevertheless, in formal writing and speech, the use of whom is still conventional.
  3. The stylistic difference is much less obvious when that is used to represent a non-personal entity, either as the subject or the object of the verb, so, for example:
        The book which I bought
        The book that I bought
        The train that arrived
    and
        The train which arrived
    are more or less synonymous, even stylistically, although even here some would consider the use of which as more formally correct.

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prepositions

Prepositions in relative clauses

Prepositions sometimes cause a few problems for learners.

think Task:
The following sentences contain prepositions.
How are these significant?
What are the rules for dealing with prepositions in relative pronoun clauses?
Click here when you have an answer.
  1. This is the car in which he arrived
  2. This is the car that he arrived in
  3. This is the car he arrived in
  4. This is the person with whom he arrived
  5. This is the person who(m) he arrived with
  6. This is the person he arrived with

There is a serious restriction on preposition positioning when the relative pronoun is that or Ø which is not parallelled in other languages and causes some difficulty.

  1. When a wh- word is the pronoun, the preposition can occur before the pronoun or be postpositioned so we allow all the following:
        The woman I spoke to
        The woman who(m) I spoke to
        The woman to whom I spoke
        The car I came in
        The car which I came in
        The car in which I came
  2. However, when we use that as the pronoun, the preposition must be postpositioned so we allow, e.g.:
        The car that I came in
        The woman that I spoke to
    but neither:
        *The car in that I came
    nor
        *The woman to that I spoke
    is acceptable.
  3. A further restriction concerns the zero (Ø) relative or omitted pronoun.  We do not allow, e.g.:
        *The woman to I spoke
    but:
       The woman Ø I spoke to
        The woman to whom I spoke
    and
        The woman that I spoke to
    are all acceptable.
    Again, the preposition must be postpositioned.

The choices are therefore reduced like this:
that choices
(Based, rather loosely, on Quirk & Greenbaum, 1973:381)

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reduced

Reduced relative clauses

Consider these sentences:

  1. The woman in the garden is my mother
  2. The woman outside is my mother
  3. The customers, unhappy with the work, complained
  4. The kid acting the fool is my sister
  5. The house built by his father is still his only home
  6. The woman, an expert on gardening, is helping my mother
think Task:
When is it possible to omit both the relative pronoun and the verb be?
Click here when you have an answer.
fused

Nominal or fused relative clauses

In the analysis above, all the examples contain both the relative pronoun and what is known as its antecedent (i.e., the noun the relative pronoun refers to).  So, for example, in
    That's the man who stole my bicycle
it is clear that the man and who refer to the same person.  So, the man is the antecedent of the pronoun who.
and in
    The tickets which we sold to my brother
the antecedent of the pronoun which is the tickets.

Frequently, however, the antecedent is either understood or simply absent.  This is why clauses of this type are sometimes called fused relative clauses (because the antecedent and the pronoun are combined) or nominal relative clauses (because the whole clause is acting as a noun).
Here are some examples:

As you see, nominalised or fused relative clauses fill the same grammatical slots as noun phrases (hence the name).

With nominal relative clauses certain relative pronouns are used:

  1. what is the most common
    1. She told him what he wanted to hear (object)
    2. What I wanted had disappeared (subject)
    3. Have you any idea what to do next? (object of the interrogative)
  2. who and which are also commonly used as object nominalised clauses
    1. I explained who was going to do the work
    2. I didn't know which to use
  3. the -ever series of pronouns are also frequent
    1. Whoever told you that is a liar
    2. Whatever you want is OK with me
    3. Whichever you decide on will be expensive

Warning: some sources will include formulations such as
    How(ever) you do it is your business
    Whenever he comes is OK with me
but these are, in fact, relative adverbs, not relative pronouns (and the subject of a different guide linked in the list of related guides at the end).
If the word refers to when, how or why, it is not a relative pronoun, it's a relative adverb and they function significantly differently.  To mix them up, and hence confuse your learners, is unwise.
Some wh- and that-clauses occur in what are known as cleft sentences and there is guide to these on this site linked in the list of related guides at the end.

Unlike other nominal clauses, nominal relative clauses can act as the indirect object so we allow, for example:
    I'll give whoever asks a new book.

There are also structures called free relative clauses and those, too, are considered in the guide to relative adverbs because they share some characteristics.  As you will see, if you go to that guide, this site takes the view that nominalisation is a better way to think about such things.

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position

The position of the relative clause

As we have seen in many of the examples in the guide so far, relative pronoun clauses can occur in medial position in a sentence, with or without the object pronoun.  For example:
    The man (whom) you met was my boss
    The book (which / that) you took was mine.
    The person who sold me the car has left the country
etc.

Relative pronoun clauses are also frequently found in the final position in sentences because they typically introduce new information (and that is a common phenomenon in English called end focus).
The other reason, discussed more fully below, is that they are quite heavy grammatically and English prefers heavier elements at the ends of clauses.
The antecedent is commonly an indefinite pronoun such as one of the any- or some- series or an indefinite noun phrase such as a person, a child, a thing, a tool etc.  For example:
    I’m looking for someone who can help me write a website
    We need something which can act as a counterbalance
    Can you find us a local who can show us the way?
    I don't have the tool that will do the job
    Is that the man whose father is an MP?
etc.
This position is common with an existential there is / there are structure.  For example:
    Is there anyone here who can help me?
    There is something over there that looks like a snake
    There are some things (that) I always forget to pack
etc.
By the nature of such sentences, the relative pronoun is often the subject and cannot, therefore, be omitted.

chair

Extrapositioning

Relative clauses are also subject to a phenomenon called extra-positioning in which the clause is sent to the end of the sentence, after the verb phrase.  For example, the usual sentence might be:
    The man who wants to complain about the service just came in
but the relative clause can also be extra-positioned to get:
    The man just came in who wants to complain about the service
The second form is notably rarer and more difficult for many learners to unpack.  It also marks the relative clause in concordance with the principle of end focus, i.e., gives it added emphasis.

Non-defining relative clauses almost always occur in medial position so we can have:
    My sister, who lives in America, may be able to help you with that
but not:
    *My sister may be able to help you with that, who lives in America

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stack

Stacking pronoun relative clauses

Relative pronouns clauses can also be stacked in the final position so we can have, for example:
    That is the book I got from the library which I like but that you hate
In theory, there is no limit to how many relative pronoun clauses can be stacked in this way but native speakers stop at two or three.

This is less common in medial position because of the cognitive overload produced by trying to say (and understand) something like:
    Have you given the food which I cooked and that you hated but which the guests enjoyed to the dog?

Non-defining clauses, probably up to a maximum of two, can be stacked in medial position.  For example:
    His brother, who lives in France and who speaks French, may be able to translate that.
It is possible to have more than two of these, providing they are short enough so, e.g.:
    His brother, who lives in France, speaks French, can be contacted by email and is usually helpful, may be able to translate that
is possible but that's about the limit of the cognitive load with which speakers and listeners can cope.

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shocked

Sentence relative clauses
... which shocked me  

There is an odd form of relative clause in which it is not possible to identify an antecedent noun phrase because the reference is not to a particular person or object but to the whole of a preceding sentence (or even a longer text).  The name for this varies in the literature but here we will refer to them as sentence relative clauses although you may find them called comment clauses and a number of other things.
Only one of the five pronouns can function this way: which.
Here are some examples:

    They fell in love and got married, which astonished everyone they knew.
    After the rain, the garden flourished, which was no surprise.
    Once we had had the meeting, matters improved, which was welcome.

These clauses are generally separated from the antecedent text by commas because they are, in fact, non-defining, in the sense that the preceding text can sensibly stand alone.
They always follow the text to which they refer.
It is not possible to omit the pronoun.

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languages

Other languages

Relative clauses in English come after the noun to which they refer.  The reason for this has to do with how elements are ordered in English in terms of what is known as heaviness.
A heavy element of a clause is more grammatically and lexically complex than a light one.  For example, modifying a noun with a determiner or simple adjective as in:
    that car
    a car
    the car
    three cars
    red car
is a very light way to do so and English prefers light elements to precede the noun so we do not get
    *car that
    *cars a
    *car the
    *cars three
    *car red
and so on.
This is not the case, incidentally, in a range of other languages, including Yoruba and many African languages as well as Thai and many other South-East Asian languages.

However, modification with a complex prepositional phrase will normally follow the noun because it is a heavier element than a single determiner or adjective so we have, e.g.:
    the car over there with the broken headlight
not
    *the over there with the broken headlight car.
Relative clauses are just about the most complex way in which noun phrases can be modified in English so it is unsurprising that the clauses follow the noun they modify or refer to.  That is not a universal tendency of all languages but it is one shared with most European languages.
Chinese languages, for example, do not follow the end weighting rule and place the relative clause before the object or subject noun (see below for a little more).

The ways in which other languages form relative clauses is very varied and first-language interference errors are common when learners are acquiring the system in English.
Here's brief run-down of the most important differences.  It behoves you to find out how your learners' first language(s) handle the area so you are prepared for the interference issues and can focus on salient differences.  If you are a native or very competent speaker of your learners' first language(s), this just requires a little thought.  In other circumstances, it requires a little research.

  1. who vs. which
    ferret
    Many languages, including but not limited to: Dutch, Albanian, Scandinavian languages (including Finnish, this time, and Icelandic), German (in which relative pronouns closely parallel the form of the definite article), Spanish, French, Italian, Malay / Indonesian, Latvian, Maltese, Portuguese, Greek, Russian, Polish (and other Slavic languages including Slovak, Czech and Slovene etc.), Persian languages (Farsi, Dari, Tajik) and Thai do not distinguish between a pronoun referring to people and one referring to inanimate objects and animals.  In most languages, therefore, there is no pronoun distinction between
        The wind which came in
    and
        The man who came in
    so errors such as
        *That's the man which I saw
        *That's the table who he bought in France
    etc. are frequent and have to be handled by making sure that the distinctions in English between who and which are very clear.
    A serious problem is the fact that the pronoun which can sometimes be used to refer to people with whom the speaker is unfamiliar.  When learners are exposed to such expressions, they may, quite naturally, assume that which can be used for all human antecedents.  This is especially the case with collective nouns for groups of people so, for example, we can allow:
        The committee which considered the matter was convinced
    and
        The committee who considered the matter were convinced
    but it is worth noticing that when who is the preferred relative pronoun, verb-subject concord becomes an issue and in BrE (but not usually in AmE) who may be followed by a plural form of the verb but which is invariably singular.  There is more on concord issues below.
    Speakers of these languages, aware that English is different in this respect, may be tempted to play safe and overuse that in grammatical environments where it is not allowable (i.e., in non-defining or non-restricted clauses).  Errors such as:
        *The Eiger, that is in The Alps, is a beautiful mountain
    or
        *The bus, that I take every morning, was very late today
    will occur.
    Additionally, that is often unacceptably informal, especially in writing, and that leads to stylistic error.
  2. that and what
    gorilla
    Some languages use that and what interchangeably (German, Modern Greek and Dutch are commonly cited examples) and that can lead to errors like
        *That's the man what he said would come
        *The wind what came in
        *The man what came to the meeting
    etc.
    In some non-standard varieties of English, this also happens but it is almost universally considered erroneous.
    The use of what as a relative pronoun is confined, in this analysis, to its occurrence in fused or nominal relative clauses as in, e.g.:
        I don't know what she wants to do
    Introducing such clauses too early to learners whose first languages use that and what interchangeably is unhelpful.
  3. Non-parallel structures
    non-parallel
    Even languages which sometimes distinguish between pronouns for people and things do so in ways which do not parallel English at all.
    In French, for example, different pronouns are used depending on whether the object or the subject is the reference (que and qui respectively) but both can be used for animate and inanimate nouns.
    Italian uses different pronouns depending on whether the noun is followed by a preposition or not (cui and che respectively).
    Portuguese has a single relative pronoun (que) which can refer to people or things but this changes to quem when preceded by a preposition.  The word quem is only used to refer to people and means who or whom.
    All of these differences can lead to interlingual errors because of temptation to assume that differences like these are parallelled in English.
    A further non-parallel aspect is the use of which as a sentence relative clause to refer to a preceding text rather than an identifiable antecedent noun phrase.  Most languages will not use a pronoun in this way, preferring something like ... and that + the comment or using an equivalent of what.
  4. Omitting the pronoun
    omit
    Most languages which use relative pronouns as subordinators do not allow the pronoun to be omitted and, apart from causing speakers to sound unnaturally formal with sentences such as
        The book which I read explains it well
    instead of the much more natural
        The book I read explains it well
    this also presents comprehension difficulties because learners from these backgrounds will have problems understanding
        Is she the woman you spoke to?
    or
        That's the program you should run
    because there are no obvious pronoun clues to what the object of the verb really is.
    Languages which do not allow the pronoun omission are in the majority and include most of those listed in point 1, above.
    The omission of the pronoun in English, incidentally, causes serious problems for machine translations for the same reason that comprehension issues arise.
  5. Preferring pre-modification
    modify
    There are two associated issues here:
    1. Many languages, as we saw above, do not comply with the rule that heavy elements need to be positioned to the right in a clause and these languages usually avoid post-modification via relative clauses.  We may get, therefore:
          *The agreed by the majority decision
      when most English speakers would prefer:
          The decision which was agreed by the majority
      However, even in English, when the relative pronoun clause is comparatively simple (i.e., light) such pre-modification is allowed so we might prefer:
          The admitted truths
      rather than:
          The truths which were admitted
      or
          The respected authorities
      rather than:
          The authorities who are respected
      Nevertheless, this is something to handle with a little care in the classroom because as soon as the modification becomes even slightly heavier, the post-modifying rule kicks in.  So, for example, we might allow:
          The middle house
      instead of:
          The house which is in the middle
      we do not allow
          *The in the middle of the street house
      and can only have:
          The house (which is) in the middle of the street
      In fact, any additional prepositional phrase usually results in the prohibition of pre-modification so we cannot allow, e.g.:
          *The end of the garden gate
      and must insist on:
          The gate (which is) at the end of the garden.
      in which we can reduce the relative clause or not as we please because we are complying with the heaviness-to-the-right rule.
    2. The secondary restriction not parallelled in many languages that concerns the permanence of the attribute so, while we can look at a photograph of a group of people and speak of:
          The end woman
      rather than
          The woman who is at the end
      because the photograph is permanent and fixed in time.  We cannot do that when the situation is fluid and changing so:
          *The end woman
      is not allowed if we are describing something current and mobile.
      To see what is meant, we can also, for example, distinguish between:
          The central table
      pre-modifying the table and referring to its permanent position and
          The table which is in the centre
      post-modifying the table and implying that it can (and may be) moved.
      We cannot, of course, make that distinction in other circumstances so, for example:
          The central room
      and
          The room which is in the centre
      are synonymous.
  6. Restricted and non-restricted uses
    restrict
    A range of languages, including Russian, German, Dutch and Polish, do not distinguish between restricted (defining) clauses and non-restricted (non-defining) clauses and that can cause punctuation, pronunciation and comprehension errors.  In German, for example, all relative clauses are separated by commas, not just non-defining clauses as in English.
    For speakers of other languages, in which the comma is used to separate sense groups rather than represent pausing, similar issues arise.
  7. Concord
    handshake
    Most languages (including American varieties of English) are strict about concord and will strive to make verb and pronoun forms match the number and characteristics of the subject.  British English is sloppier in this respect and, depending on their notion about the nature of the subject, British English speakers can accept, for example:
        The group who were asked to work on the project
    and
        The group which was asked to work on the project
    but will not allow
        *The group which were asked to work on the project
    or
        *The group who was asked to work on the project
    This will lead to some error because most learners will assume that English has the same grammatical regard for concord that their languages exhibit.
    Other concord errors will occur, such as:
        *The range of students which was accepted for a place at the university
    which follows a grammatical rule (range is non-animate and singular and so should be followed by which and a singular verb form) but is unacceptable to most English speakers who would prefer:
        The range of students who were accepted for a place at the university
    These are examples of issues with notional and proximity concord respectively in English.  For more on concord, follow the link below.  In this case,
  8. Absence of relative pronouns and clauses
    empty
    You will search in vain for mention of relative pronouns in the grammars of many languages, including Turkish (usually), Korean, Tamil and Japanese, for the simple reason that these languages do not use them at all and no closely equivalent structures exist.
    In most, the meaning is expressed either through compound adjectives, so we get:
        *The by the river house
    instead of
        The house (which is) by the river
    or by participle clauses so we get, e.g.:
        *My friend living in America invited me to visit him
    instead of
        My friend who lives in America invited me to visit him
    Some of these language, Turkish being an obvious example, do have a structure similar to a relative clause but the language uses non-finite forms rather than the finite ones which English prefers.  So, for example, a Turkish speaker will have little difficulty understanding or producing:
        The car sitting in front of the house is his
    but will not naturally produce and may have difficulty understanding
        The car which broke down is in front of the house
    and may attempt something like:
        *The car breaking down is in front of the house
  9. Resisting subordination
    no
    South Asian languages in particular resist subordination altogether, preferring other ways to express the fact that one part of a sentence depends on the understanding of another, and speakers of these languages (which include many in the subcontinent such as Hindi and Urdu) may have difficulty seeing the reason for relative clauses at all and struggle with both the forms and the whole concept of subordination in general.
  10. Clause ordering
    order
    Finally, in Chinese languages, there are parallel structures but in these languages, the relative clause precedes rather than follows the noun phrase and that can produce errors such as:
        Who is in England my friend wrote to me
    Additionally, the pronoun may routinely be omitted regardless of the grammatical function it performs and that leads to errors such
        *The man gave me the money was very friendly
    This will also affect languages which use adjectival phrases or participle clauses to express the concepts (see point 7) because these structures also precede the noun and they may produce errors such as
        *The parking the car woman ...
    instead of
        The woman (who is) parking the car
    or
        *The book buying the man is very expensive
    instead of
        The book (which) the man is buying / bought is very expensive
    The distinction between the times when one can and cannot omit the pronoun and the ordering of the clauses need careful work.

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teach

Teaching relative pronoun clauses

Step 1 for any teaching, especially to people whose first languages do not have relative pronoun clauses or which use them very differently, is to focus on getting the form right.  We saw above how the rules work for making simple subject relative clauses by following three easy steps.  This can be done as a classroom exercise like this:
example

You will probably have to come up with a few more pairs of simple sentences like these, using both which and who, preferably, because that caters for people whose first languages do not distinguish, to give people adequate practice in forming relative pronoun clauses embedded in sentences.  It is not easy for many learners.
You can also, of course, use the little video (above) to explain how the clauses are formed.

Once the form of relative clause is mastered, you can move on.

If you have been following up to now, you will know that this is not a simple system in English and the restrictions, as we saw above, are important.  In particular, we (and, eventually, our learners) need to be aware of:

And these are just some of the issues you need to know about and analyse before you can begin to tackle the area.
For this reason, careful selection of model texts or other presentation texts is very important.
If the text you select contains multiple examples of relative pronouns as subjects, as objects, including that, reduced, with omitted pronouns, in nominalised clauses and so on you are asking for trouble.  This will be compounded if you also fail to distinguish between relative pronouns and relative adverbs.  For examples of the horrible, confusing mishmash that doing so produces, search the web for lessons in the area.  Alternatively, pick up any of a range of classroom coursebooks whose authors have neglected to do the research.

At lower levels in particular, you need to focus very carefully, introducing, say, only defining relative clauses using who and which as subject pronouns in model sentences such as
    He is the student who asks lots of questions
or
    That is the car which sat outside my house all night
Getting lower-level learners to form such sentences from:
    He is the student
    He asks lots of questions
or
    That is the car
    It sat outside my house all night
is a good beginning but it can't stop there, of course.

window

The window: a neglected classroom aid

A quickly set up exercise to practise relative pronoun clauses is to get your learners to look out of the classroom window and tell you what they see.  With a bit of priming and nudging from you, that can elicit comments such as:
    I can see a car which is parked illegally
    There is a traffic warden who is putting a ticket on it.
    The people whose car it is will be really upset
etc.
Clearly, this can't be done until the forms have been presented and practised a little but it works well.

learners

The learners: another neglected classroom aid

Using your learners' own experiences (their internal world) can also be productive and it is not hard to set up practice routines to evince statements like:
    We went on holiday to New York last year which I found fascinating.
    We have a room in the house which we only use for guests.
    I remember a great teacher who really inspired his students.
etc.
It's up to you to limit and elicit the correct pronouns.

A semi-controlled practice idea is simple to get the learners to say something true about three other people in the room (including you, if you like) and three things they know about.  That can evince statements such as:
    Paul is the guy who always knows the right answer.
    Mary is the person who sits near the door
    This is the coat Mary wore this morning
    That's the pen Arthur stole from me
and so on.
It's a personalised and engaging exercise and that, so the theory goes, makes the structures memorable.

photograph

The students' mementos: another neglected classroom aid

An associated idea is to ask the learners to bring in half a dozen favourite photographs or souvenirs and get them to explain what they are of or where they came from.  That can evince language such as
    It's a bag I bought in Tunisia
    It's a photograph that I took in Russia
    This is the girl whom I met in London
and so on.
This works particularly well for practising the omission of the pronoun because, by their nature, the items are generally the objects of defining relative clauses.

The next step is to introduce the range (excluding that for which special rules apply) until the learners can construct acceptable subordinating clauses using which, who(m) and whose.
Then it's time to focus on when the pronouns can be omitted (restricted to defining clauses where the object is denoted by the pronoun, and excluding whose).

Finally, the range of reduced clauses can be tackled along with nominalised or fused relative clauses.  That can be done alongside consideration of wh-question forms because the structures are more or less parallel:
    I don't know what to wear
is not far removed grammatically from:
    Do you know what to wear?
and
    Do you know who arrived late?
because both have a nominalised wh-clauses as the object of the verbs.

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Summary

Here's a brief cut-out-and-keep summary of the area:

summary

Here's another summary of the main kinds of relative clauses with two examples of each.

example summary


Related guides
relative adverbs for more on another form of relative clause using adverbs
theme and rheme toto discover other ways in which key parts of discourse are connected other than by the use of relative clauses
wh-questions for more on how wh-clauses are used in English
cleft sentences for an area allied to the use of nominalised relative clauses
subordination for more on other ways to make ideas depend on other ideas
ambiguity which considers the role of relative pronoun clauses in disambiguation

Click here for two tests in this area.
The first test just asks you to match the type of relative clause to an example.  The second test is a bit more searching.

References:
Campbell, GL, 1995, Concise Compendium of the World's Languages, London: Routledge
Celce-Murcia, M and Larsen-Freeman, D, 1999, The Grammar Book – An ESL/EFL Teacher’s Course, 2nd ed., Boston: Heinle
Chomsky, N, 2002, Syntactic Structures (2nd Edition), New York: Mouton de Gruyter
Dryer, MS and Haspelmath, M. (Eds.), 2013, The World Atlas of Language Structures Online, Leipzig: Max Planck Institute for Evolutionary Anthropology
Parrott, M, 2000, Grammar for English Language Teachers, Cambridge: Cambridge University Press
Quirk, R & Greenbaum, S, 1973, A University Grammar of English, Harlow: Longman
Swan, M and Smith, B, 2001, Learner English, 2nd Edition, Cambridge: Cambridge University Press
Yule, G, 1998, Exploring English Grammar, Oxford: Oxford University Press