介词+WHICH在
定语从句中可以代替when,where,和why，用哪一个介词要看
先行词和从句
谓语动词，介词要能够与先行词搭配使用
、"介词+
关系代词"引导的定语从句
关系代词whom, which在定语从句中作介词的宾语时,可以跟介词一起放在主句和从句之间;当先行词指人时,介词后的关系代词用whom, 其余用which,这时的关系代词不能省略;有时为了使关系代词紧跟它所修饰的先行词,也可以把介词放在从句中有关动词的后面,这时的which可用that替换。当介词放在从句有关动词的后面时,关系代词which, that, whom在口语中和非正式文体中经常省略。如:
This is the room in which he used to live. = This is the room (which / that) he used to live in. 这是他过去居住过的房间。
Who's the man with whom you just shook hands? =Who's the man (that / whom) you just shook hands with? 刚才你与他握手的那个人是谁?
但含有介词的短语动词一般不拆开,介词仍放在动词的后面。如:
This is the book (which / that) I'm looking for. 这就是我在找的那本书。
在这类定语从句中,介词的选择一般根据动词的需要,如上述几例,或者根据先行词来决定。如:
There is a mountain of which the top is always covered with snow. 有一座山顶总是覆盖着雪的山。
哪些短语动词在定语从句中不可将介词或副词与动词分离
1.含有介词的动词短语固定搭配一般不拆开使用，如：look for, look after, take care of等
(1) This is
the watch which/that I am looking for. (T)
(2) This is the watch for which I
am looking.
(F)
2.若介词放在关系代词前，关系代词指人时用whom，不可用who或者that；指物时用which，不能用that；关系代词是
所有格时用whose
(1)
The man with whom you talked is my friend. (T)
(2) The man with that you
talked is my friend. (F)
(3) The plane in which we flew to Canada is very
comfortable. (T)
(4) The plane in that we flew to Canada is very comfortable.
(F)
(这里的talk with sb,fly in the plane,并不属于固定搭配,是直接就可以凑成的搭配,所以其介词可以提前)
定语从句中何时使用“介词+关系代词”
一、“介词＋关系代词”的用法
当关系代词在定语从句中作介词宾语时，我们通常用“介词＋关系代词”引导定语从句。如果指“人”，用“介词＋whom”；如果指“物”，用“介词＋which”。例如：
Do you know the lady with whom our manageris talking in the office?
Where is the supermarket in which youbought the laptop last week?
使用“介词＋关系代词”要注意以下几点：
(一)选用介词的依据：
(1) 根据定语从句中谓语动词的搭配习惯(即固定短语)。例如：
Yesterday we visited the West Lake forwhich Hangzhou is famous.
(2) 根据先行词的搭配习惯(约定俗成，不一定是短语)。例如：
The
old woman with whom you talked just nowis a famous artist.
(3) 根据句子的意思来选择。例如：
The naughty boy made a hole in the wallthrough which he could see what is happening outside.
(4) 表示“所有”关系或“整体中的一部分”时，通常用介词of。例如：
I have about 20 books, half of which were writtenby Bing Xin, the famous writer.
(二)在定语从句中，含介词的短语动词不可拆开使用(短语拆开后含义发生变化)，如look after, look for等。例如：
The babies whom the nurses are lookingafter are very healthy.(正)
The babies after whom the nurses arelooking are very healthy.(误)
(三)“of which /whom”有时可以用“whose＋名词”结构来改写。例如：
The building whose roof was damaged in theearthquake has been repaired.
＝The building of which the roof was damaged in the earthquake hasbeen repaired.
(四)当先行词为way并且定语从句中缺少状语时，通常用in which或that引导定语从句(in which或that可省略)；如果定语从句中不缺少状语，则用关系代词引导(that 或which 可省略)。例如：
All of us disliked the way(in which /that)Tom settled the maths problem.
I don’t understand the way(that/which)theteacher explained to me.
(五)in that不可以引导定语从句，但可以引导
原因状语从句。例如：
She didn’t attend the meeting in that /because she was seriously ill.
二、“介词＋关系代词”与
关系副词的转化
(1)当先行词表示地点，定语从句中缺少地点状语时，通常用关系副词where引导，此时也可选用表示地点的介词＋which来代替关系副词where。例如：
I visited the village where many childrencouldn’t go to school because of poverty.
＝I visited the village in which many children couldn’t go toschool because of poverty.
(2) 当先行词表示时间，定语从句中缺少时间状语时，通常用关系副词when引导，此时也可选用表示时间的介词＋which来代替关系副词when。例如：
We’d better fix a date when we willpractice speaking English next week.
＝We’d better fix a date on which we will practice speaking Englishnext week.
(3) 当先行词为reason，定语从句中缺少表示原因状语时，通常用关系副词why引导，此时也可以用for which来代替关系副词why。例如：
Can you tell me the reason why you werelate for school?
＝Can you tell me the reason for which you were late for school?