Relative pronouns

The relative clauses give us information about the subject or object of s main clause. Defining relative clauses describe exactly which (or what kind of) person or thing we mean:

Arthur Conan Doyle is the written who invented Sherlock Holmes.

Do you have a phone which takes photos?

We introduce a relative clause with a relative pronoun:

Relative pronoun: who for people example:
Mrs Lee was the woman who taught me to play the piano

Which for animals or things but NOT people, example:

Their cat has killed the rat which was living under our house.
I've got a water heater which uses solar power.

That for people, animals and things, example:

Sue's got a car that loves coffee!
It's a phone that takes photos.

Whose for possession and relationships (his, her, it's, or their), example:

I know the woman whose husband used to be your boss.
Hannah owns a horse whose coat is completely white.