介词+关系代词
“介词+关系代词”引导的定语从句是定语从句的一种复杂形式，这类定语从句的关系代词主要有which ,whom , whose , 它们既可以引导限定性定语从句，也可以引导非限定性定语从句。关系代词前该选用什么样的介词，要根据不同的语境、习语、惯用法等来决定。
一．介词选择的主要标准
1.介词与定语从句的先行词是一种习惯性搭配
Human facial expressions differ from those animals in the degree to which they can be controlled on purpose.人类的面部表情和动物的面部表情就可控制的程度来说是不一样的。( to a degree )
The gentleman about whom you told me yesterday proved to be a thief.你昨天告诉我的那个绅士被证明是个小偷。( tell sb. about sb./ sth. )
The English play in which my students acted at the New Year’s party was a great success.那场在新年晚会上我学生参加表演的英语剧很成功。( in the play )
The schools themselves admit that not all children will be successful in the jobs for which they are being trained.学校本身承认，并不是所有的孩子都能在他们所接受的培训的职业成功。( be trained for the job )
2.介词与定语从句中的动词是一种习惯性搭配
Who is the man with whom our teacher is shaking hands? 我们的老师与之握手的那个男士是谁？ ( shake hands with sb. )
Last month , part of Southeast Asia was struck by floods , from whose effects the people are still suffering. 上个月，东南亚的部分地区发生洪水，人们还在遭受着洪水所带来的影响。(suffer from sth. )
3.介词与定语从句中的形容词构成一种习惯性的搭配
Ours is a beautiful country , of which we are greatly proud . 我们的国家是一个美丽的国家，我们为之感到很自豪。( be proud of )
The woman to whom Spielberg is married is an actress. 同斯皮尔伯格结婚的女人是一位演员。( be married to )
The West Lake , for which Hangzhou is famous, is a beautiful place. 西湖很美，杭州以西湖而闻名。( be famous for )
The woman to whom he was engaged was a doctor. 他与之订婚的那个女士是位医生。(be engaged to )
4.有时关系代词前用什么介词，要根据句子的意思来决定，此时不但要注意其前的搭配，也要注意其后的搭配
I was a woman running toward me in the dark. Before I could recognize who she was, she had run back in the dark.Before I could recognize who she was , she had ran back in the direction from which she had come.看见一位妇女在黑暗中像我走来，我还没来得及认清她是谁，她已经从她来的方向跑回去了。（如果仅注意先行词，很容易受习惯心里的影响而使用in this direction 的搭配，但考虑到语境后的come ，则应该使用from。）He was educated at the local high school, after which he went on to Beijing University. 他在当地一所高中上学，之后他上了北京大学。（after which 的意思就是“在当地一所高中接受完教育之后”）。
In the office I never seem to have time until after 5:30 pm. by which time many
have got home.在办公室我好像总是没时间，只有等到下午五点半，而那个时候大家都已经回家了。（此句不能受at 5:30 pm 的通常表达的影响而选用介词at, 而应该依据整个句子的语意来确定介词。）
5.表示“所有格”或“整体与部分关系”时，用介词of
The journey around the world took the old sailor nine months, of which the sailing time was 226 days.这次环球旅行老水手用了9个月，其中航行的时间是226天。
The factory produces half a million pairs of shoes every year, 80% of which are sold abroad. 这个工厂每年生产50万双鞋，其中的（指50万双鞋）80%销往海外。
I was told that there were about 50 foreign students studying Chinese in the school, most of whom were from Germany.我被告知这个学校有大约50个外国学生在学习中文，其中大多数来自德国。
I have many friends,of whom some are businessmen. 我有很多朋友，其中有些是生意人。
二．介词不能提前的情况
当关系代词在定语从句中作介词的宾语时，介词可以提前放在which（指事物不能用that）或者whom(指人不能用who)之前，也可放于原来的位置，但在含有介词的动词固定短语中，由于动词和介词的关系比较紧密，一般不能将介词与动词拆开而将介词提到关系代词之前。这类短语动词有listen to/look at/depend on/take care of/look into/break into/get rid of/look forward to等。
This is the room which/that Lu Xun used to live in.(=This is the room in which Lu Xun used to live.)这是鲁迅曾经住过的房间。
The man
