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.