“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 degreetowhichthey 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 )Thegentlemanaboutwhomyoutoldmeyesterdayprovedtobeathief.你昨天告诉我的那个绅士被证明是个小偷。
( tell sb. about sb./sth. )TheEnglishplayi nwhichmystudentsactedattheNewYear’sparty 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 )Theschoolsthemselvesadmitthatnotallchildrenwillbesuccessful in the jobsforwhichthey 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 trainedfor 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 manwith whomour 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 ,from3.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 whichwe 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 womanto whomSpielberg 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 whichHangzhou is famous, is a beautiful place.西湖很美，杭州以西湖而闻名。
( be famous for )The womanto whomhe 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 couldrecognize who she was, she had run back in the dark.Before I couldrecognize who she was , she had ran back in the directionfromwhichshe 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 whichhe went on toBeijingUniversity.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ofThe journey around the world took the old sailor nine months,ofwhichthe 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 studyingChinese in the school, mostof whomwere 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 whomsome 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listento/lookat/dependon/takecareof/lookinto/breakinto/getridof/lookforward to等。
Thisistheroomwhich/thatLuXunusedtolivein.(=Thisistheroomin whichLu Xun used to live.)这是鲁迅曾经住过的房间。
The man1) Have you ever dreamed of playing in front of thousands of peopleataconcert,atwhicheveryoneisclappingandappreciatingyourmusic?2)Theymaystartasagroupofhigh-schoolstudents,forwhompractising their music in someone’s house is the first step to fame.3) Later they may give performances in pubs or clubs, for which theyare paid in cash.4)Themusiciansweretoplayjokesoneachotheraswellasplaymusic, most of which was based loosely on the Beatles.5)However,afterayearorsoinwhichtheybecamemoreseriousabouttheirwork,the Monkeesstartedtoplayandsingtheirownsongs like a real band.6) Theyproduced a new record in 1996, with which theycelebratedtheir former time as a real band.“介词+关系代词”引导的定语从句，是定语从句一种介词前置的定语从句句型，介词与关系代词之间存在一种介宾关系。
当关系代词在定语从句中作介词宾语时，把介词置于关系代词前，即演变出“介词+关系代词”句型。
例如：The man who/whom /that you spoke to is a teacher.=The man to whom you spoke is a teacher.一、基本构成1.“介词+关系代词”结构引导的定语从句中，关系代词只能用which（指物）或whom(指人)，即：介词+which/whom。
（1）The man to whom you spoke is a teacher.cartoons.注意：当介词放在关系代词的前面时，用在介词后的关系代词不能省略。
2.关系副词when，where，why可用“介词＋which”来代替。
关系副词实际上是介词＋先行词。
其中when=表时间的介词（如：in，at,on,during等）+which；Where=表地点的介词（如：in，at,on,under等）+which；Why=表原因的介词（如：for）+which(1)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。
I still remember the day when I came here. ( on theday =when)(2)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。
This is the house where I lived last year. ( inthe house= where)(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。
There are many reasons why people like traveling. (for thereasons =why注意：1.含有介词的短语动词一般不拆开,介词仍放在短语动词的后面。
如: lookfor, look after, take care of，pay attention to, look forward to等。
most, each, few等代词或者数词,表示先行词的一部分或全部。
He loves his parents deeply, both of whom are very kind to him.In the baskettherearequitemany apples,some of which havegonebad.二．介词的选择根据从句中动词与先行词的逻辑关系。