Examples of the relative clause and relative pronouns

It is not the easiest grammar point. I will give you some examples.

•  Who is for people and sometimes pet animals.

Peter phoned the parents, who then phoned the son.

• Which is used for animals and things.

We drove past my old school, which is closing down this year

• That can be used for people, animals, and things but is informal. 

He went to the school (that) my father went to.

• Whose is possessive and is used for mainly people and animals.

There was me and there was Kate, whose birthday party it was.

• Whom is used in written form instead of who, if who is the object.

Drama in colleges is very good for students for whom English is a second language.