只能用that,不用which 的情况：
(1) 先行词是all, few, little, nothing, everything, anything 等不定代词时。如：
All that he said is true.
(2) 如果先行词被形容词最高级以及first, last, any, few, much, no, some, only, very等词修饰，关系代词常用that,不用which。如：
This is the best book (that) I have read this year.
This is the only book that the old woman is interested in.
(3) 先行词是序数词或被序数词修饰的词。如：
It was the second house that I bought.
(4) 先行词既包括人又包括物时。如：
He talked about the people and the things that he remembered.
（5）当主句是以who，which开头的特殊疑问句或先行词是who时，只能使用“that”
Which is the book that he borrowed from the library yesterday?
只使用which，不能用that的情况：
(1) 在非限制性定语从句中。如：
I will take this one, which was exactly what we wanted.
(2) 定语从句由介词+关系代词引导，先行词是物时。如：
The thing about which he is talking is of great importance.
(3) which的特殊用法，它可以引导从句修饰前面的整个主句，which可以作主语，也可以作宾语或表语，多数情况下意思是与and this相似。如：
He succeeded in the competition, which made his parents very happy.
关
系
副
词
when ：指时间，在定语从句中作状语。如：
I’ll never forget the time when we worked on the farm.
where ：指地点，在定语从句中作状语。如：
This is the house where we lived last year.
why：指理由，前面一般是 reason。在定语从句中作状语,如:
I dont know the reason why he was late.
【attention：】
关系副词相当于‘介词+which’。
关
系
代
词
who：在定语从句中作主语或宾语。如：
The boy who is wearing the black jacket is very clever.
whom：指人，在定语从句中作宾语。如：
Mr. Lee (whom) you want to see has come.
whose：指人，在定语从句中作定语。如：
I know the boy whose father is a professor.
that：多指物，有时也指人，在定语从句中作主语或宾语。如
I’ve read the newspaper that / which carries the important news.
which：指物，在定语从中作主语或宾语。如：
Here is the book (which) the teacher mentioned yesterday.
功
用
结
构
在复合句中，修饰某一名词或代词的从句叫做定语从句。
被定语从句修饰的词叫先行词。
定语从句必须放在先行词之后。
引导定语从句的关联词有关系代词和关系副词。如：
This is the present that he gave me for my birthday.
Do you know everybody who came to the party?
