Relative clauses

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.

I like books. Books are interesting.
→ I like books that are interesting.

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).

Try the following exercise: