第一部分:基础知识（一）定语从句概述定语可以由形容词，代词，数词，名词，不定式，介词短语来充当。如果是一个句子担任定语，那么这个句子就叫做定语从句，又可称为形容词性从句。定语从句通常修饰某一名词或代词，被定语从句修饰的这一名词或代词叫先行词，它位于定语从句之前，定语从句在先行词后面，应尽量紧跟先行词。定语从句的作用即在于对先行词进行限定说明或补充说明。（二）定语从句的引导词。定语从句的引导词分为两类：关系代词（that, which, who, whom, whose ）关系副词（ when, where, why ）引导词在先行词和定语从句之间，既起连接作用，即连接先行词和定语从句，更重要的是，它又作定语从句中作一个成分。（三）关系代词1. that 指人，物，在从句中作主语，宾语，表语。This is the photo that I took in the country.He is the singer that I met yesterday.2. which 指物，在从句中作主语，宾语，在非限定定语从句中充当定语，或者代替前句The film which we saw last night was moving.3. who 指人，在从句中作主语，宾语。The person who visited our classroom yesterday was our new headmaster.The man who you just talked to is Tom.4. whom 指人，在从句中作宾语。That is the professor whom you want to know.5. whose 指人，物，在从句中作定语，相当于先行词+ s, 后接一名词。I know the boy whose parents are dead.I dont like those cities whose roads are dirty.【注】：关系代词在从句中作宾语时可以省略。关系代词有六个，听我逐一来说破；which表物人用who,人物都有that顾；which用在逗号后，意表前句你要know;who做主语很称职，whom用到宾语里；（四）关系副词关系副词在从句中作状语，有时相当于介词+which，其中which指代先行词不可以指示整个句子。1，when 指时间，在从句中作时间状语，相当于at/ on/ in/ during which.Ill never forget the day when (on which ) I reached the top of the Huangshan Mountain.2，where 指地点，在从句中作地点状语，相当于at/ in / to/ which.This is the school where( at which ) I studied.3，why 指原因，在从句中作原因状语，相当于for which.Thats the real reason why (for which ) he was late.第二部分：关系代词的特殊用法（一）关系代词指物时, 用that而不用which的情况:1，先行词为something ,anything ,nothing ,everything以及all , much , little , a lot , none , few等不定代词时。My mother was so proud of all that I did2，先行词有the last , the very , the only以及all , much , few , no , any ,little等修饰时。This is the very book that Im looking for .3，先行词为序数词、形容词最高级(或所修饰)时。This is the most exciting film that Ive ever seen .When people talk about Hangzhou , the first that comes to their mind is the West Lake .4，the same 修饰先行词时 , 定语从句要用that 或as引导 , 但意义不同。This is the same watchas I lost last Sunday . (表示相同但并非同一)This is the same knife thatI used yesterday . (表示就是那个)5，先行词既有人又有物时, 只能用that。Do you remember the book and its author that appeared on TV last Sunday6，There be 后面的定语从句多用that引导 , 不用which 。Theres a seat in the corner that is still free . 7，句子前面出现了who , which 时 , 后面的定语从句用that引导。They built a factory which made some new products that had never been seen before .Who is the man that you were talking about just now ?8，关系代词在定语从句作表语时, 常用that , 而不用which 、who 。My home town is not the small village that it was 10 years ago .Tom isnt the man that he used to be (二) 关系代词指人时, 有时只用who ,而不用that。1，先行词为指人的代词one , those , the man,以及人称代词如he等。Those who are often late for school should be punished .He who doesnt reach the Great Wall is not a true man .2，先行词为someone (somebody), no one (nobody), anyone (anybody), everyone (everybody) 。Anyone who would like to attend the party should come on time .3，先行词指人时, 如有序数词, 最高级, the very , the only ,the last等修饰 , 定语从句既可用that也可用who引导。He is the first student who / that worked out the problem .(三) 关系代词whose的用法：1， whose 在从句中作定语 ，表示“先行词的” ，既可指人，也可指物。John is my best friend , whose father is a scientist .The old man lived in the house whose window was broken .The boss , in whose company my father worked , was very friendly to the workers .2，whose 可以转换为of which（物）和of whom（人） 。1) The dictionary whose cover is missing is mine . ( 划线部分可改为the cover of which或of which the cover )2) They also invited Mr Wang , whose car was stolen last Sunday . ( 划线部分可改为 the car of whom 或 of whom the car )(四) which的特殊用法：1， 关系代词which引导的非限制性定语从句 , 有时不是修饰某个先行词 , 而是指代主句的全部或部分内容 。特别注意，非限定定语从句中prep+which 时，which 只能指代先行词，不可以指代句子。1）In China , you sometimes get a hot damp cloth to clean your face and hands , which ,however , is not the custom in western countries .2）Helen often came late , which made the class teacher angry . 2，which 有时可在定语从句中作定语 , 含义上相当于指示代词this / that 。1) He stayed in England for 5 years , during which time he learned English well . 2) It may rain hard tomorrow , in which case I wont go fishing .【注】： which的这种用法与whose 作定语不同 。whose 表示“ 先行词的”。Theyre talking about a film , whose name I have forgotten . 3，以介词结尾的动词不定式作定语时 , 可借关系代词which把介词前置。1）Tomorrow would be Christmas Day , and she had only $ 1.87 with which to buy Jim a present .2）Those poor people had no houses to live in / in which to live . 【注】 如果先行词指人，关系代词用whom 。I want to find a person to travel to England with / with whom to travel to England .(五) 关系代词as的用法：1. 引导限制性定语从句：当先行词有such , so , the same等修饰时, 关系代词要用as ； as在从句中可作主语，宾语和表语。1) . I have never seen such a kind girl as she is .2) . He is such a good teacher ( so good a teacher ) as every student respects .比较：He is such a good teacher ( so good a teacher ) that every student respects him . ( 此句为such / so that引导的结果状语从句 )3) . Such a student as often studies hard is sure to pass this exam .4) . He bought the same bike as I did last week .