1，概念:定语可以由形容词、名词、代词、分词、不定式以及介词短语等来担任，也可以由一个句子来充当，充当定语功能的句子称为定语从句。
2，定语从句“三要素”1.先行词：被定语从句所修饰的名词或代词①指人的先行词②指物的先行词★ 先行词还可以是前面整个句子所叙述的事情。He has passed the driving test, which surprises all of us.(which替代前面所叙述的事情)先行词2.关系词：引导定语的词(1)关系词的作用①替代前面的先行词（替代作用）②连接主句和定语从句（连接作用）③在定语从句中作句子成分（成分作用）(2)关系词的分类①标准：根据关系词在从句中做的句子成分种类②关系代词：在从句中做 主，宾，表，定（that/which/who/whom/whose/as）③关系副词：在从句中作状语(When/where/why)3.定语从句：用来做定语，修饰限定先行词的句子3，定语从句的分类:1.限制性定语从句：对先行词起限定修饰作用。He is a teacher who works at our school.2.非限制性定语从句：对先行词起补充说明作用(先行词与定语从句之间有逗号隔开)Beijing, which is the capital of China, is a beautiful city with a long history.比较：He has two sons, who work in the same company.(He has only two sons.)He has two sons who work in the same company.(Perhaps he has two more sons)4，定语从句的10个难点:1.关系代词的省略(限定性定语从句)(1)关系代词在定语从句中作宾语She is the girl (whom / that) I loved before. (可以省略whom/that)(2)关系代词在定语从句中作表语He is no longer the boy (that) he used to be.(可以省略that)(3)关系代词作介词宾语，介词在从句句尾时可以省略Housing price is a problem (that/which) people are interested in.比较：Housing price is a problem in which people are interested.（此时只能用which且不能省略）2.先行词是人(that/who的区别)(1)用that的情况①以疑问词who开头的句子中Who is the man that is shouting there?②关系代词在从句中作表语时She is not the girl that she used to be.③先行词被the very, the right, the only修饰This is the very person that we are looking for.(2)用who的情况①先行词是one, ones, anybody, all, none, those 等Those who want to go to the cinema will have to wait at the gate of the school.②句子中有两个定语从句,一个用了that,另外一个用whoWho is the boy that won the gold medal?③在there be 结构中There are many young men who are against him.④在非限定性定语从句当中Tom, who is my best friend, has gone abroad to study.3.先行词是物(that / which的区别)(1)用which的情况①在非限定性定语从句中She lost the game, which depressed her greatly.②关系词置于介词之后，作宾语The pen with which you write is Jack’s.③先行词是that或定语从句中套定语从句,一个关系词用that,另一个用which.Let me show you the novel that I borrowed from the library which is newly open to us.(2)用that的情况①先行词是不定代词如all, little, few, much,anything, everything, nothing, none, no one等She did all that she could to help us.②先行词被all, every, no, some, little, much, the only, he very, the right，the last等所修饰时This is the very book that I want.③先行词中既有人又有物时She described in her compositions the people and he places that impressed her most.④先行词前有序数词或形容词最高级修饰时This is the best book that I have ever read.This is the first film that I’ve seen since I came here.⑤定语从句中套定语从句，其中一个关系词以用which, 另外一个用thatHe built a factory which produced things that had never been seen before.⑥当主句的主语是疑问词which,另一个用thatWho is the person that is standing at the gate?4.As引导定语从句用法(1)As 既可以引导限制性定语从句也可以用于非限定性定句中充当主语，宾语，表语等。常用于以下句型当中：Such/so….. as….像…..一样the same …. as… 和…...同样的A computer is so useful a machine as we can use everyday.He is not the same man as he was.(2)引导非限制性定语从句，此时译为“正如，像”等。可以放在句首，句中或句末。As I remember, there were a net bar here.Taiwan is an inseparable part of China, as is known to all.★the same as...和the same that...引导定语从句的区别This is the same bike that I lost yesterday. (同一事物)This is the same bike as I lost yesterday. （同类事物）5.关系副词的运用(1)When 在定语从句中做时间状语，先行词为表示时间的time, day等I still remember the day when I first came to Beijing. (when=on which)(2)Where 在定语从句中做地点状语，先行词为表地点的place, spot等Can you tell me the office where he works?(where = in which)(3)Why 在定语从句中做原因状语，先行词只有reason.I don’t want to listen to any reason why you were absent.(why = for which)★ 关系副词 = 相应的介词 + 关系代词★ Where引导的定语从句还可以修饰抽象空间的名词如case(情形)，situation, position(位置),stage (阶段)，point（地步）等What are the situations where body language is the only form of communication?在哪些情况下身体语言是唯一的沟通方式。(此时where = in which)6.几个特殊的先行词(1)way在定语从句中做状语时的三种引导方式 that / in which / 不填The way in which / that / 不填 he explains the sentence to us is quite simple.比较：The way which /that/不填 he told to us was quite simple.★way在定语中作tell的宾语(2)先行词timetime表示“次数”时，用关系代词that引导定语从句This is the first time that the president has visited the country.time作“一段时间” 讲时，应用关系副词whenThis was the time when there were no radios, no telephones or no TV sets★此时when = during which 在..期间(3)先行词reason当在定语从句中作状语时，定语从句的4种引导方式 why/for which/that/不填This is the reason why/for which/that/不填 he can not come here.比较：Is this the reason that/which/不填he explained to us for his absence from the conference.★reason 在定语从句中做explain的宾语7.介词+关系代词★该结构的关系代词只有两种即 介词+which（指物） 介词+whom（指人）★该结构介词的选用原则：(1)根据定语从句中谓语动词的习惯搭配This is the book on which I spent $ 8.This is the book for which I paid $ 8.(2)根据先行词的搭配习惯I remember the days during which I lived there.I remember the day on which I graduated from university.
