如题所述
when是和时间有关的，what不参与构成定语从句，which是和事件，物体，概念等有关的，in which相当于在which里，也就是在有关的事件，物体，概念里。
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第1个回答 2015-02-12
when 放在时间词的后面，in which 放在地点后面，相当于where, which放在名词后面，what在句子中充当宾语或主语，不能用在定语从句中。各个举个例子吧
Do you know the time when he will arrive?
I don't know what he says.
Do you know the place in which they will stay?
Do you like the food which you have eaten?
Do you know the time when he will arrive?
I don't know what he says.
Do you know the place in which they will stay?
Do you like the food which you have eaten?
第2个回答 2015-02-12
when是什么时候，what是什么，which是哪个，in which从句中一般有和in搭配的短语，只是这里将in提前
第3个回答 推荐于2017-09-28
简单来说，
1.when主要用于修饰表时间的名词，同时它在定语从句中用作时间状语。如：
There comes a time when you have to make a choice. 你必须作出抉择的时候到了。
2.what引导名词性从句，不引导定语从句。
3.in which=where where=in/ at/ on which（介词根据不同的先行词搭配）
主要用于修饰表地点的名词，同时它在定语从句中用作地点状语。如：
This is the village in which(where) he was born. 这就是他出生的村子。
4.which在定语从句中指物，可作主语或及物动词或介词的宾语，作宾语时可省略。
The package (which/that) you are carrying is about to come unwrapped.你拿那个包裹快要散开了。本回答被提问者和网友采纳
1.when主要用于修饰表时间的名词，同时它在定语从句中用作时间状语。如：
There comes a time when you have to make a choice. 你必须作出抉择的时候到了。
2.what引导名词性从句，不引导定语从句。
3.in which=where where=in/ at/ on which（介词根据不同的先行词搭配）
主要用于修饰表地点的名词，同时它在定语从句中用作地点状语。如：
This is the village in which(where) he was born. 这就是他出生的村子。
4.which在定语从句中指物，可作主语或及物动词或介词的宾语，作宾语时可省略。
The package (which/that) you are carrying is about to come unwrapped.你拿那个包裹快要散开了。本回答被提问者和网友采纳
