用that不用which的情况：
1.先行词是不定代词或被不定代词修饰，如much, little, none, all, few, everthing, anything.等
例句：
Is there anything that I can do for you.
(这里有什么，我可以为你做的事吗？)
The boy has little money that he got from his boss.
(这个男孩从他老板那里得到了一点钱)
2.当先行词是序数词或最高级修饰时，或者先行词就是序数词或最高级时。
例句：
The first thing that I should do is to review my lessons.(第一件我需要做的事就是复习我的课程。)
The Old man and Sea is the most interesting
book that I have read.(老人与海是我读过最有趣的书。)
3. 当先行词有the very, the same, the only,vthe last 修饰时。
例句：
This is the only thing that I can do now.
4.当先行词以who, 或which开头时。
例句：
Which is the pen that you lost.
(哪一个是你丢的笔？)
5.先行词同时包含人或物时。
They talked about the teachers and the schools that they know.
(他们讨论着他们所知道的学校和老师。)
只用which的情况：
1.先行词本身就是that时。
例句：
Whats that which flashed in the sky just now.
(那是什么，刚刚在天空一闪而过。)
2.关系代词前有介词且指物时。
例句：
The house in which I used to live has become a clothes shop.
(我曾经住的那个房子现在变成了一个衣服商店。)
上次知识回顾：
that:先行词是人/物;可在从句中做主语/宾语。
例句:
1.She is the girl that I called three times
yesterday.(她就是那我昨天叫了三遍的女孩。)
分析: 先行词是girl(人); that 在从句中充当called的宾语。
2.This is the girl that called me three times
yesterday.(这就是那个叫我三遍的)
分析: 先行词是girl(物); that在从句中充当主语
which：先行词是物;可在从句中作主语，宾语。
例句：
1.This is the book that my father bought for
me. (这就是我爸爸给我买的书。)
分析：先行词是book; that 在从句中作宾语。
牛刀小试:
1.This is one of the best films _______.
A. that have been shown this year
B. that have shown
C. that has been shown this year
2.Is there anyone in your class ______family is in the country?
A. who B. whos C. whose
3. I want to use the dictionary ______was used yesterday.
A. which B. who C. what
4. He talked a lot about things and persons ________they remembered in the school.
A. which B. that C. whom
5. In our factory there are 2,000 workers, two thirds of ____are women.
A. them B. which C. whom
6. The man ______hair is white is American.
A. which B. whose C. what
7.Do you know the woman about her information _____ is crying over there?
A. who B. whoseC. which
