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 manager is talking in the office?
你认识正在办公室和经理谈话的那位女士吗？
Where is the supermarket in which you bought the laptop last week?
你上周买笔记本电脑的那家超市在哪？
使用"介词＋关系代词"要注意以下2个点：
(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 for which Hangzhou is famous. （be famous for)
昨天我们参观了著名的杭州西湖。
(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 now is a famous artist. (talk with)
刚才和你谈话的那位老太太是位著名的艺术家。
(3) 根据句子的意思来选择。例如：
The naughty boy made a hole in the wall through which he could see what is happening outside. (see through...）
那个淘气的男孩在墙上挖了一个洞，通过这个洞可以看到外面发生了什么事。
(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 written by Bing Xin, the famous writer. (=of 20 books，在20本书当中）
我大约有20本书，其中有一半是著名作家冰心写的。
(二)在定语从句中，含介词的短语动词不可拆开使用(视为整体)，如look after（照顾）, look for（寻找）等。例如：
The babies whom the nurses are looking after are very healthy. (正)
护士照顾的那些婴儿非常健康。
The babies after whom the nurses are looking are very healthy. (误)look after 是整体，不能拆分二、"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 children couldn't go to school because of poverty. =I visited the village in which many children couldn't go to school because of poverty.
我昨天参观的那个村庄，因为贫穷那里的许多孩子不能上学。
(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 will practice speaking English next week.＝We'd better fix a date on which we will practice speaking English next week.
下周我们最好确定一个练习说英语的日期。
(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 were late for school?＝Can you tell me the reason for which you were late for school?
你能告诉我你上学迟到的原因吗？