Relative clauses let you join two ideas in one sentence. Instead of saying "I have a friend. She speaks five languages," you can say "I have a friend who speaks five languages." The relative clause comes right after the noun it describes.
There are two kinds. A defining relative clause tells us which person or thing we mean, and the sentence is unclear without it. A non-defining relative clause only adds extra information, and commas separate it from the rest of the sentence. This small difference decides which words you can use and whether you need commas.
Relative pronouns and adverbs
Choose the word according to what the clause describes: a person, a thing, a possession, a place or a time. The clause comes right after the noun.
| Type | Pattern | Example |
|---|---|---|
| who | people | The doctor who treated me was very kind. |
| which | things and animals (defining or non-defining) | The bus which goes to the airport is late. My bike, which is ten years old, still works. |
| that | people or things, only in defining clauses | Is this the key that opens the back door? |
| whose | possession: whose + noun | I met a woman whose son plays for the national team. |
| where | places | That's the restaurant where we first met. |
| when | times | I'll never forget the day when I got my first job. |
- Defining clauses have no commas, and that can replace who or which. Non-defining clauses always have commas, and that is not possible.
- When the relative pronoun is the object of the clause, you can leave it out in a defining clause: The movie (that) we watched was boring. When it is the subject, you must keep it: The man who called you is here.
- Don't repeat the subject or object inside the clause: the man who lives here (not the man who he lives here).
- Prepositions usually go at the end of the clause in everyday English: the town (that) I grew up in. In formal English, the preposition can go before which or whom: the town in which I grew up.
- Whom is a formal object form of who: the person whom I contacted. In everyday English, most people use who or that, or leave the pronoun out.
- Many American style guides recommend that rather than which in defining clauses (the book that I lent you). This is a style preference, not a grammar rule: which is also correct in defining clauses and is common in British English.
When to use relative clauses
1. Defining relative clauses: saying which one
A defining clause identifies the person or thing you mean. Without it, the sentence would be unclear or incomplete. Don't use commas.
- The girl who won the race is only twelve.
- Did you get the email that I sent you?
- People who exercise regularly usually sleep better.
2. Non-defining relative clauses: extra information
A non-defining clause adds information about someone or something that is already clear. Put commas around it, and use who or which, never that.
- My grandmother, who is 90, still walks every day.
- My new phone, which I bought in March, has already stopped working.
- We spent a week in Lisbon, which we loved.
3. Whose for possession
Use whose + noun to show that something belongs to the person or thing before it. It replaces his, her, its or their.
- That's the boy whose bike was stolen.
- I have a friend whose father is a famous chef.
- We stayed in a village whose houses are all painted blue.
4. Where and when for places and times
Use where after a noun of place and when after a noun of time. You can also say the same thing with which/that + a preposition: the house where I was born = the house (that) I was born in.
- This is the town where my parents met.
- Do you remember the summer when it didn't rain at all?
- Friday is the day when the market is busiest.
5. Leaving out the relative pronoun
In a defining clause, you can leave out who, which or that when it is the object of the clause, that is, when another subject comes after it. This is very common in speech. You cannot leave it out when it is the subject: The man who lives next door is a pilot.
- The book (that) you lent me was fantastic.
- She's the person (who) I told you about.
- Is this the jacket (which) you wanted?
6. Prepositions at the end of the clause
When the relative pronoun is the object of a preposition, everyday English puts the preposition at the end. In formal writing, the preposition can come first, followed by which for things or whom for people, never that.
- That's the man (who) I was talking to.
- The apartment we're looking at has two bedrooms.
- She loves the company she works for. (formal: the company for which she works)
Examples
Positive
- The woman who lives upstairs is a nurse.
- I finally found the book that I lost last month.
- Our teacher, whose husband is Brazilian, speaks excellent Portuguese.
- This is the park where I learned to ride a bike.
Negative
- I don't like people who are always late.
- The hotel that we booked didn't have a pool.
- He isn't the person I was expecting.
- My car, which isn't very old, broke down again yesterday.
Questions
- Do you know anyone who can fix a laptop?
- Have you seen the movie that everyone is talking about?
- What's the name of the town where you grew up?
- Is that the neighbor whose cat keeps sleeping on our car?
Defining or non-defining?
A defining clause tells you which person or thing; a non-defining clause adds extra information about someone or something already identified. Commas can change the meaning, so compare these pairs carefully.
| Defining (no commas) | Non-defining (with commas) |
|---|---|
| My brother who lives in Canada is a doctor. (I have more than one brother) | My brother, who lives in Canada, is a doctor. (I have only one brother) |
| The students who passed the test got a certificate. (only some of them passed) | The students, who passed the test, got a certificate. (all of them passed) |
| You can use that: the phone that I bought | You can't use that: my phone, which I bought last week |
| An object pronoun can be left out: the phone I bought | The pronoun can never be left out: my phone, which I bought last week |
Common mistakes
- WrongThe man which lives next door is a pilot.RightThe man who lives next door is a pilot.
Use who (or that) for people; which is for things and animals.
- WrongI know the man who he lives next door.RightI know the man who lives next door.
Who is already the subject of the clause, so don't add he.
- WrongMy mother, that is a teacher, loves books.RightMy mother, who is a teacher, loves books.
That cannot introduce a non-defining clause (one with commas), so use who or which.
- WrongThis is the book I told you about it.RightThis is the book I told you about.
The relative clause already refers to the book, so don't add the pronoun it at the end.
- WrongThe town where I grew up in is very small.RightThe town where I grew up is very small.
Where already includes the meaning of in, so don't add another preposition (or say the town I grew up in).
- WrongThat's the woman who's car was stolen.RightThat's the woman whose car was stolen.
Whose shows possession; who's means who is or who has.
The bookstore on the corner
Examples of relative clauses are highlighted.
Near my office there is a small bookstore that I visit almost every week. The owner, who opened it in 1998, is a retired teacher called Rosa. The shop is in an old building where a bakery used to be, so it still smells a little like bread. At the back, there is a corner where children can sit on cushions and read. Rosa remembers every customer who comes in more than twice, and she knows the books they love. Last month, I found a novel that I had been looking for since college. It was by a writer whose books are very hard to find. Rosa, who had saved it for me, just smiled. That was the moment when I knew I'd never shop anywhere else.
Relative Clauses quiz
8 questions. Choose an answer to see if it is right and why.
Read texts that use relative clauses
Grammar sticks when you meet it again in real reading. These graded texts use this structure; each one has key words, audio and questions.
Relative Clauses: questions and answers
What is a relative clause?
A relative clause is part of a sentence that describes a noun. It usually starts with who, which, that, whose, where or when and comes right after the noun: The man who called you is my uncle.
What is the difference between that and which?
In defining clauses (no commas), both that and which can refer to things, although American style guides often prefer that. In non-defining clauses (with commas), only which is possible: My car, which is old, still runs well.
When can I leave out who, which or that?
You can leave it out in a defining clause when it is the object of the clause: The book (that) I read was great. You can't leave it out when it is the subject (the man who lives here) or in a non-defining clause.
When do I use commas with relative clauses?
Use commas when the clause only adds extra information about someone or something already identified: My father, who is 60, loves jazz. Don't use commas when the clause tells us which person or thing we mean: The people who live upstairs are very noisy.
Can a relative clause end with a preposition?
Yes. In everyday English, the preposition often goes at the end: This is the song I was talking about. In very formal writing, some people put it first instead: the song about which I was talking.