Do you know the man whose name is Wang Yu?

2.which引导的定语从句：which在从句中作主语或谓语动词和介词的宾语。例如：

This is the book which you want.

The building which stands near the river is our school.

The room in which there is a machine is a workshop.

3.由that引导的定语从句：that在定语从句中可以指人或物，在从句中作主语、谓语动词或介词的宾语。（但不能放在介词后面作介词宾语）例如：

The letter that I received was from my father.

注意在下面几种情况下必须用that而不用which引导定语从句：

①先行词是不定代词all, few, little, much, something, nothing, anything等。例如：All that we have to do is to practise every day.

②先行词被序数词或形容词最高级所修饰。例如：The first lesson that I learned will never be forgotten. This is the best film I've ever seen.

③先行词被all, any, every, each, few, little, no, some等修饰。例如：I have read all the books(that)you gave me.

④先行词被the only, the very, the same, the last修饰时，例如：He is the only person that/(who) I want to talk to .

⑤先行词既有人又有物时，例如：They talked of things and persons that they remembered.

⑥当句中已有who时，为避免重复。例如：Who is the man that is talking to John?

⑦用作关系代词，修饰表示时间的名词如day, time, moment等，代替when。例如：It happened on the day that/when I was born.

⑧如有两个定语从句，其中一个关系词已用，则另一个用that。例如：Edison built up a factory which produced things that had never been seen before.

4.由when, where, why引导的定语从句。例如:

I know the reason why he came late.

This is the place where we lived for 5 years.

I will never forget the day when I met Mr Liu.