which表示在一定范围内的“哪一个”,可当主语、宾语、定语.
定语从句的关系代词 Which的用法:若先行词指物则代替先行词在定语从句中充当主语或宾语.
This is the pen which was given by my friend.
先行词 指物代替先行词在定语从句中充当主语
This is the pen which my friend gave to me.
先行词 指物代替先行词在定语从句中充当宾语
which在定于从句中经常和that相混
下面是他和that在定语从句中的区别及用法：
that which在代物时常常可以通用,但有时只宜于用which ,不用that
(1) 关系代词前有介词时.
This is the hotel in which you will stay.
(2) 如有两个定语从句,其中一句的关系代词是that,另一句宜于用which.
Let me show you the novel that I borrowed from the liberary which was newly open (新开放) to us.
注意2that which在代物时常常可以通用,但有时只宜于用that ,不用which.
(1) 先行词是形容词最高级或者它的前面有形容词最高级时
This is the best that has been used against air pollution(反对空气污染) in cities.
English is the most difficult subject that you will learn during these years.
(2) 先行词是序数词,或它的前面有一个序数词时
He is the last person that I want to see.
(3) 主句中已有疑问词时
Which is the bike that you lost?
(4) 先行词既有人又有物时
The bike and its rider that had run over (撞倒了)an old man were taken to the police station.
(5) 先行词是all,much,little,something,everything,anything,nothing,none,the one等代词时
You should hand in all that you have.
We haven’t got much that we can offer you.
I mean the one that you talked about just now.
(6) 先行词前面有only,any,few,little,no,all,one of,the same,the very等词修饰时
The only thing that we can do is to give you some money.
Li Ming is the only one that got full marks (满分)in our class.
Li Ming is one of the students that want to be teachers in our class.
(7) 有两个定语从句,其中一个关系代词已用which,另外一个宜用that
Edison built up a factory(办了一个工厂) which produced things that had never been seen before.
定语从句的关系副词 Where的用法:若先行词指地点且其在定语从句中充当地点状语.
This is the house+I was born in the house.(=I was born there)
介词短语 副词
=This is the house where I was born.这就是我在那儿出生的房子.
先行词 关系副词
in which I was born.
介词+关系代词
which I was born in.
关系代词
这里作介宾的which和that可以省略
that I was born in
which在名词性从句的用法：
1.宾语从句
which是一个连接代词,在宾语从句中可以充当主语,宾语或定语.意思是“哪一个”如：I don't know which bike belongs to my father.
I wonder which is better ,this one or that one?
He asked me which I liked best.
2.主语从句
which 在主语从句中的用法与宾语从句相类似.
which boy she likes best is still a mystery.
Which students will be sent to take part in the sports meeting hasn't been decided.
3.表语从句
which 在表语中的用法与主语从句和宾语从句的用法也相似.
如：His question is which student is the best at English.
The question is which place he wants to go to .
4.同位语从句
which在同位语从句中的用法不多,只用在某些名词的后面,常见的有idea.
I have no idea which picture is the most beautiful of all.
顺便讲一下,what引导的名词性从句,也是连接代词,但表示的是泛指的东西；which指的是在一定的范围内,哪一个.