relative pronouns

The relative pronouns are:

Subject	Object	Possessive
who	who(m)	whose
which	which	whose
that	that

We use who and whom for people, and which for things.
Or we can use that for people or things.
We use relative pronouns:
• after a noun, to make it clear which person or thing we are talking about:

the house that Jack built
the woman who discovered radium
an eight-year-old boy who attempted to rob a sweet shop

• in relative clauses to tell us more about a person or thing:

My mother, who was born overseas, has always been a great traveller.
Lord Thompson, who is 76, has just retired.
We had fish and chips, which is my favourite meal.

But we do not use that as a subject in relative clauses.
We use whose as the possessive form of who:

This is George, whose brother went to school with me.

We sometimes use whom as the object of a verb or preposition:

This is George, whom you met at our house last year.
This is George’s brother, with whom I went to school.

But nowadays we normally use who:

This is George, who you met at our house last year.
This is George’s brother, who I went to school with.

When whom or which have a preposition the preposition can come at the beginning of the clause...

I had an uncle in Germany, from who[m] I inherited a bit of money.
We bought a chainsaw, with which we cut up all the wood.

… or at the end of the clause:

I had an uncle in Germany who[m] I inherited a bit of money from.
We bought a chainsaw, which we cut all the wood up with.

We can use that at the beginning of the clause:

I had an uncle in Germany, that I inherited a bit of money from.
We bought a chainsaw, that we cut all the wood up with.