只用that不用which的情况：
1、当先行词是all, little, few, much, something, everything, anything, nothing, none等不定代词时。如：
Everything that happened then was like a nightmare.当时发生的一切就像是一场噩梦。
2、当先行词被only, any, few, little, no, all, just, very（恰好的，表示强调）等词修饰时。例如：
The only thing that we could do was to wait.我们能做的只是等待。
3、当先行词是序数词、形容词最高级或先行词被序数词或形容词最高级修饰时。例如：
The first place that we visited was the Great Wall.我们参观的第一个地方是长城。
4、被修饰词为数词时。例如：
Yesterday I caught two fish and put them in a basin of water. Now you can see the two that are still alive. 昨天我捉到了两条鱼，把它们放在一盆水里。你可以看到那两条鱼还活着呢。
5、主句是There be结构，修饰其主语的定语从句宜用that作关系代词修饰物。例句：
There's still a room that is free.还有一个空房间。
扩展资料：
that的用法：
that用作指示代词的意思是“那,那个”。可指前面提到的那件事,也可指在空间或时间上较另一事物远的事物或人,还可指要表明的或要提及的事物、想法等。
that用作关系代词时,指人或事物,同时又在从句中充当句子成分。that偶尔也可引导非限制性定语从句。
that还常用以代替who, whom, which,但that...which中的that用做关系代词的先行词。
that用作关系代词时在下列情况下可以省略：
1、引导限制性定语从句在从句中用作宾语时；
2、用在there be结构前作主语时；
3、用作表语时；
4、在定语从句与先行词之间有插入语时；
5、在先行词way, reason, distance, place, office等作方式状语、原因状语或地点状语时。
that用作连词时可引导主语从句、宾语从句、表语从句、同位语从句和状语从句。
that还常引导间接引语或形容词后面的从句。
that在以it作形式主语的句子中或引导宾语从句、状语从句时常可省略。
1、当先行词本身是all, everything, anything, nothing, none, little, few等代词时，关系代词原则上用that，不用which，例如：
In China, parents always do everything that they can to support their children.
在中国，父母总是尽他们所能来抚养孩子。
I did nothing that might hurt you.
我没有做任何可能伤害你的事。
2、当先行词被all, every, no, little, few, the only, the very, the right(恰当的), the last, the same等修饰时，关系代词原则上用that，不用which，例如：
Chatting is the only thing that interests her most.
聊天是她唯一感兴趣的事情。
These messages are the very ones that I have been looking for.
这些就是我一直在寻找的信息。
3、当先行词本身是序数词或形容词最高级，以及被序数词、形容词最高级修饰时，关系代词原则上用that，不用which，例如：
It was the largest map that I ever saw.
那是我见过的最大的地图。
When it comes to Jinan, the first that comes to mind is the spring water.
谈到济南时，首先想到的就是泉水。
扩展资料
只能用which不用that的情况：介词后面，逗号后面。
1、介词后面，指物的关系代词只能用which；
The house in which we live is very old.
我们住的房子非常老。
2、逗号后面，指物的关系代词只能用which。
I live in Beijing, which is the capital of China.
我住在北京，中国的首都。
本回答被网友采纳1、当先行词本身是all, everything, anything, nothing, none, little, few等代词时，关系代词原则上用that，不用which。
例如：In China, parents always do everything that they can to support their children.
在中国，父母总是尽他们所能来抚养孩子。
2、当先行词被all, every, no, little, few, the only, the very, the right(恰当的), the last, the same等修饰时，关系代词原则上用that，不用which。
例如：Chatting is the only thing that interests her most.
聊天是她唯一感兴趣的事情。
3、当先行词本身是序数词或形容词最高级，以及被序数词、形容词最高级修饰时，关系代词原则上用that，不用which。
例如：It was the largest map that I ever saw.
那是我见过的最大的地图。
4、先行词既指人又指物。
例如：We talked about the person and things that we remembered.
5、句中已经有who或which时，避免重复。
例如：Who is the man that is making a speech?
扩展资料
只能用which不用that的情况：
1、在“介词＋关系代词”结构中，关系代词必须用which。
This is the reference book of which the teacher is speaking.
这就是老师正在谈及的那本参考书。
注意： 如果介词不放在修饰事物的限定性定语从句的句首， which就可换为that， 例如： This is the question which/that we've had so much discussion about. =This is the question about which we've had so much discussion. 这就是我们已经多次讨论过的问题。
2、先行词为“those＋表事物的复数名词”时， 关系代词通常只用which而不用that。
如：you should grasp well those skills which may be used in future work.
最后当先行词是表示原因或方式的名词时，可以用that引导定语从句，相当于介词+which，that可以省略。
如： She likes the child for the very reason that (=for which) she loves his father. 她喜欢那个孩子因为她爱着孩子的父亲。
He didn't like the way that (=in which) she speaks to his mother.
他不喜欢她对他的母亲那样说话。
本回答被网友采纳一、以下情况不能用that,只能用which：1、在非限定性定语从句中,逗号之后不能用that；2、介词后面不能用that.
二、以下情况不能用which,只能用that：
1、前面的先行词是不定代词时,如 all ,anything ,nothing,the one 等；
2、如果先行词出现了the only ,the very 时；
3、如果先行词出现了序数词和形容词最高级时；
4、如果先行词中既有人又有物时,如：They are talking about the school and the teachers that they visited yesterday.追答
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本回答被提问者采纳