定語從句中的關係代詞who，whose，whom，that，which。

who作為從句的主語或賓語

I know the girl who is Tom"s sister.

Do you know the man who I just talk with?

whose充當物主代詞 “誰/什麼的”

That is the old man whose son is our headmaster.

Don"t sit on the chair whose leg is broken.

whom 充當賓語，放介詞之後

That is the man with whom I just talk.

Peter is the boy from whom I borrow a bike.

that 多數代替事物，也有很少的時候代替人

this film is the best one that I have ever seen.

which 代替事物，主語賓語都可以指代。

I want to visit the factory which I worked in three years ago.