Introduction to Relative Clauses
Relative clauses add information about a person, thing, place or time. They allow us to combine ideas without repeatedly using short, separate sentences.
Compare:
I spoke to a woman. She works at the university.
Using a relative clause:
I spoke to a woman who works at the university.
The relative clause who works at the university identifies or describes the woman.
Relative clauses often begin with a relative pronoun or relative word such as who, which, that, whose, where or when.
They are useful because they help us create more natural, detailed and complex sentences:
The book that you recommended was excellent.
My brother, who lives in Bristol, is visiting next week.
This is the café where we first met.
There are two main types: defining relative clauses and non-defining relative clauses. More advanced writers can also use reduced relative clauses to make sentences shorter and more concise.
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What is a relative clause?
A relative clause is a dependent clause that gives information about a noun. It cannot normally stand alone as a complete sentence.
The student who answered the question received a prize.
The noun being described is the student. The relative clause is who answered the question.
The noun before the relative clause is called the antecedent. The relative word connects this noun to the information that follows.
Relative clauses can describe:
- people
- things
- animals
- places
- times
- possession
Examples:
The man who called earlier left a message.
I found the keys that I had lost.
We visited the village where my grandmother grew up.
Sunday is the day when I prepare my lessons.
She is the writer whose novel won the award.
The type of relative clause determines whether the information is essential and whether commas are needed.
Defining relative clauses
A defining relative clause identifies exactly which person or thing we mean. The information is essential to the meaning of the sentence.
The students who completed the assignment can leave early.
This does not mean that every student can leave. It refers only to the students who completed the assignment.
The laptop that I bought last year has stopped working.
The relative clause tells us which laptop has stopped working.
Defining relative clauses do not use commas.
Correct:
The people who live next door are very friendly.
Incorrect:
The people, who live next door, are very friendly.
Adding commas changes the meaning by making the clause non-defining.
In defining clauses, we can use:
- who for people
- which for things
- that for people or things
- whose for possession
- where for places
- when for times
Examples:
The teacher who helped me was very patient.
The film which won the award was made in Wales.
The course that starts in September is already full.
The employee whose desk is near the window is my manager.
This is the building where I used to work.
I remember the day when we first met.
A long relative clause can separate the main subject from its verb. Review subject-verb agreement to make sure the verb still agrees with the noun being described.
Non-defining relative clauses
A non-defining relative clause adds extra information about a person or thing that is already clearly identified.
My brother, who lives in Bristol, is visiting next week.
The listener already knows which brother the speaker means. The information about Bristol is additional rather than essential.
Taipei 101, which was once the world’s tallest building, is a major tourist attraction.
The proper name already identifies the building. The relative clause simply adds extra information.
Non-defining relative clauses must be separated from the main sentence with commas.
When the clause appears in the middle of a sentence, use a comma before and after it:
Ms Harris, who teaches chemistry, is leaving the school.
When it appears at the end, use one comma before it:
We stayed at the Grand Hotel, which overlooks the river.
Do not normally use that in non-defining clauses.
Incorrect:
My car, that is fifteen years old, still runs well.
Correct:
My car, which is fifteen years old, still runs well.
The relative pronoun cannot be omitted from a non-defining clause, even when it is the object.
Incorrect:
Edinburgh, I visited last year, is a beautiful city.
Correct:
Edinburgh, which I visited last year, is a beautiful city.
Compare these sentences:
The employees who work remotely will attend online.
Only the remote employees will attend online.
The employees, who work remotely, will attend online.
This suggests that all the employees work remotely and will attend online.
The commas therefore affect both grammar and meaning.
Who, which, that, whose, where and when
Choosing the correct relative pronoun or relative word depends on what the clause describes.
Who
Use who for people. It can be the subject or object of a defining relative clause.
Subject:
The woman who lives upstairs is a doctor.
Object:
The woman who I met yesterday is a doctor.
In formal English, whom may be used when the person is the object:
The woman whom I met yesterday is a doctor.
In everyday English, who is much more common.
Which
Use which for things and animals.
The train which leaves at nine is usually crowded.
The document, which contains confidential information, must be stored safely.
That
Use that for people or things in defining clauses.
The person that answered the phone was helpful.
The shoes that I ordered are too small.
Do not use that after a comma in a non-defining clause.
Whose
Use whose to show possession. It can refer to people, organisations, animals and sometimes things.
I spoke to a student whose application had been rejected.
We visited a company whose products are sold worldwide.
Where
Use where for places.
This is the restaurant where we had dinner.
It can often be replaced by in which or at which in formal English:
This is the restaurant in which we had dinner.
When
Use when for a time.
Do you remember the year when they moved abroad?
It can sometimes be omitted:
Do you remember the year they moved abroad?
Omitting the relative pronoun
In a defining relative clause, the relative pronoun can be omitted when it is the object of the clause.
The film that we watched was excellent.
The film we watched was excellent.
The pronoun represents the object of watched, so it may be removed.
However, do not omit the pronoun when it is the subject.
Correct:
The woman who works here speaks French.
Incorrect:
The woman works here speaks French.
A quick test is to look for another subject after the relative pronoun.
The book that I bought
The clause already contains the subject I, so that is the object and can be omitted.
The book that contains the answers
There is no other subject before contains. The word that is the subject and cannot be omitted.
Relative pronouns are also not omitted from non-defining clauses.
Reduced relative clauses
A reduced relative clause shortens a relative clause by removing the relative pronoun and part of the verb.
Active meanings with an -ing form
A relative clause with an active meaning can often be reduced to a present participle.
Full clause:
The people who are waiting outside have appointments.
Reduced clause:
The people waiting outside have appointments.
Another example:
Students who wish to apply should complete this form.
Students wishing to apply should complete this form.
Passive meanings with a past participle
A passive relative clause can often be reduced to a past participle.
Full clause:
The documents that were sent yesterday have arrived.
Reduced clause:
The documents sent yesterday have arrived.
The bridge which was damaged in the storm has reopened.
The bridge damaged in the storm has reopened.
Reductions with a to-infinitive
A to-infinitive is often used after words such as first, last, next, only and superlatives.
Amelia was the first person who completed the test.
Amelia was the first person to complete the test.
This is the most important issue that we need to discuss.
This is the most important issue to discuss.
Reduced relative clauses are common in formal and academic writing, but they must clearly describe the correct noun. They also use participles and infinitives to make sentences more concise. Our guide to gerunds and infinitives explains how these related verb forms function in English sentences.
Punctuation rules
Punctuation is one of the most important differences between defining and non-defining relative clauses.
No commas for essential information
The houses that have red doors were built recently.
The clause identifies which houses are being discussed.
Commas for additional information
Buckingham Palace, which is in London, is an official royal residence.
The building is already clearly identified.
Do not use only one comma around a middle clause
Incorrect:
My teacher, who comes from Cardiff is very friendly.
Correct:
My teacher, who comes from Cardiff, is very friendly.
The clause must be closed with a second comma. Relative clauses are also an effective way to create controlled complex sentences. IELTS learners can practise this skill in our relative clauses lesson for places and people.
Common mistakes
Using that in a non-defining clause
Incorrect:
My laptop, that I bought last year, is already broken.
Correct:
My laptop, which I bought last year, is already broken.
Using commas in a defining clause
Incorrect when only some students passed:
The students, who passed the exam, received certificates.
Correct:
The students who passed the exam received certificates.
Omitting a subject relative pronoun
Incorrect:
The man lives next door is a journalist.
Correct:
The man who lives next door is a journalist.
Repeating the object
Incorrect:
The book that I bought it was expensive.
Correct:
The book that I bought was expensive.
The relative pronoun already represents the object.
Confusing whose and who’s
Whose shows possession:
The woman whose car was stolen called the police.
Who’s means who is or who has:
Who’s coming to the meeting?
Exercises and answers
Complete the sentences with a suitable relative word. In some sentences, more than one answer is possible.
- The woman __________ teaches my son is from Liverpool.
- The phone __________ I bought last month has stopped working.
- Mr Jones, __________ office is upstairs, is the new director.
- We visited Bath, __________ is famous for its Roman buildings.
- This is the park __________ we used to play.
- I remember the day __________ I started university.
- The employees __________ arrived late missed the announcement.
- My sister, __________ lives in York, is getting married.
- The report __________ was published yesterday contains new data.
- The person to __________ you spoke is my manager.
Rewrite these using reduced relative clauses where possible.
- The students who are waiting outside can come in.
- The paintings that were stolen from the gallery have been recovered.
- Ava was the first runner who crossed the finishing line.
- The man who is wearing the blue jacket is our guide.
- Applications that are received after Friday will not be considered.
Answers and explanations
- who/that
The relative pronoun refers to a person and is the subject of the clause. - that/which, or no pronoun
The pronoun is the object of bought, so it can be omitted. - whose
Whose shows that the office belongs to Mr Jones. - which
This is a non-defining clause, so use which, not that. - where
The clause describes a place. - when, or no relative word
The clause refers to a time. - who/that
The pronoun is the subject of arrived and cannot be omitted. - who
The clause adds extra information and requires commas. - that/which
The clause identifies which report is being discussed. - whom
After a preposition, whom is the formal object form. - The students waiting outside can come in.
The active clause who are waiting becomes an -ing form. - The paintings stolen from the gallery have been recovered.
The passive clause becomes a past-participle phrase. - Ava was the first runner to cross the finishing line.
Use a to-infinitive after the first. - The man wearing the blue jacket is our guide.
The active clause is reduced to an -ing form. - Applications received after Friday will not be considered.
The passive clause is reduced to a past participle.
Relative clauses help you identify nouns, add extra information and create more sophisticated sentences. Use no commas for essential defining information, use commas for non-defining information, and omit or reduce parts of the clause only when the sentence remains grammatically clear.
Related grammar lessons
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