Adjective Clauses

An adjective clause is used to describe a noun:
The car, which was red, belonged to Young-Hee

A relative pronoun is usually used to introduce an adjective clause:
Young-Hee, who is a Korean student, lives in Victoria

The main relative pronouns are:
Who: used for humans in subject position::
Hans, who is an architect, lives in Berlin

Whom: used for humans in object position::
Marike, whom Hans knows well, is an interior decorator

Which: used for things and animals in subject or object position::
Marike has a dog which follows her everywhere

That: used for humans, animals and things, in subject or object position (but see below)::
Marike is decorating a house that Hans designed