What is a relative clause?
We can use relative clauses to join two English sentences, or to give more information about something.
I bought a new car. It is very fast.
→ I bought a new car that is very fast.
She lives in New York. She likes living in New York.
→ She lives in New York, which she likes.
Defining and Non-defining
A defining relative clause tells which noun we are talking about:
I like the woman who lives next door.
(If I don't say 'who lives next door', then we don't know which woman I mean).
A non-defining relative clause gives us extra information about something. We don't need this information to understand the sentence.
I live in London, which has some fantastic parks.
(Everybody knows where London is, so 'which has some fantastic parks' is extra information).
Defining relative clauses:
1: The relative pronoun is the subject:
First, let's consider when the relative pronoun is the subject of a defining relative clause.
We can use 'who', 'which' or 'that'. We use 'who' for people and 'which' for things. We can use 'that' for people or things.
The relative clause can come after the subject or the object of the sentence. We can't drop the relative pronoun.
For example (clause after the object of the sentence):
I'm looking for a secretary who / that can use a computer well.
She has a son who / that is a doctor.
We bought a house which / that is 200 years old.
I sent a letter which / that arrived three weeks later.
More examples (clause after the subject of the sentence):
The people who / that live on the island are very friendly.
The man who / that phoned is my brother.
The camera which / that costs £100 is over there.
The house which / that belongs to Julie is in London.
