定语从句（the attributive clause）一．什么叫定语从句？一个句子作定语就叫定语从句。
二．定语从句的结构及种类1.结构：关系词+主语+谓语+其它2.种类：限制性定语从句和非限制性定语从句三．关系词的分类及关系词1.关系代词：who，whom, whose, that ,which, as2.关系副词：when，where，why四．关系词的功用1.起连接作用，引导定语从句2.在定语从句中作一个成分——主语，宾语，状语，定语，表语。
五．什么是先行词？被定语从句所修饰的词是先行词。
六．关系词的用法1.who当先行词是指人得名词或代词，而且关系词在句中作主语时，选who。
The boy who is standing over there is Tom.He who doesn’t reach the Great Wall is not a true man.2.whom当先行词是指人得名词，而且关系词在句中作主语时，选whom.This is our English teacher whom everybody likes.3.whose①当先行词是指人的名词，而且关系词在句中作定语时，选whose.This is my deskmate whose father works in a factory.②当先行词是指物的名词，而且关系在句中作定语时，选whose.We study in a classroom whose windows face to the south.4.that①当先行词是指物的名词，关系词在句中作主语时，选that.This is a machine that can walk.②当先行词是指物的名词，关系词在句中作宾语时，选that. 另外，that可以省略。
I like the present (that) my father sent me.③当先行词是指人的名词，关系词也可选用that=whoThe boy that/who is playing football on the play ground is my brother.5.which当先行词是指物的名词时，关系词也可选用which，它在句中作主语或宾语，which=that6.下列情况下，关系词只能选用that①当先行词为不定代词something, anything, nothing, everything时Is there anything that I can do for you?②当先行词为不定代词all时Mr. Li does all that he can to do his work well.③当先行词被all, some, any修饰时These are all the things that I have done today.④当先行词被the only, the very 修饰时This is the only computer that he often turns to for help.⑤当先行词被序数词，形容词最高级修饰时This is the cleaning room that you can see here.⑥time 作先行词，前面有序数词或last修饰时This is the last time that I’ll give you pocket money.⑦尽管先行词指人，但关系词在句中作表语时。
He is no longer the child that he used to be 20 years ago⑧以who开头的特殊疑问句，尽管先行词指人。
Who is the person that is sitting on the ground ?⑨当先行词包括人和物时。
7. 下列情况下，关系词只能选which①在非限制性定语从句中。
This is my favorite pen, which I bought yesterday.②先行词不是一个词，而是前面整个句子的概念时The boy is very polite, which makes his parents happy.③当先行词指物，用“介词+which”This is the pen with which I often write.8. asAs 引导定语从句时，有四种情况。
As在句中作主语，宾语。
①as 单独引导定语从句。
As we all know (=As is known to us all), Yao Ming is a famous basketball player.②the same …as…与…一样I have the same idea as you.③such… as…和…一样Don’t read such a book as you can’t understand.④as…as…和…一样In this library, you can borrow as many books as you can.9. where①当先行词是指地点的名词，而且关系副词在句中作状语时，选where，where=介词+whichThis is the classroom where we study.②尽管先行词是指地点的名词，但关系词在句中作主语，宾语时，只能选that/which.This is the factory that/which makes paperThis is the factory(that/which) we visited yesterday.③尽管先行词是指地点的名词，关系词在句中作主语，宾语，但非限制性定语从句只能用whichThis is the school, which he visited.④the one 是代词，代替前面的名词，其后的that/which 往往省略。
Is this factory the one you visited?⑤当situation, job, mark, race, point 等模糊概念的名词，关系词在句中作状语时，选whereYou’d better make a mark where you have any questions.⑥尽管先行词是指地点的名词，关系词在句中作状语，但定语从句末有介词时，选which。
This is the lab which we do experiments in.10.when①当先行词是指时间的名词，而且关系副词在句中作状语时，选when，when=介词+whichWe will never forget the days when we stayed with Mr. Smith.②尽管先行词是指时间的名词，但关系词在句中作主语，宾语时，选that或which。
Monday is the day which/that comes before Tuesday.We will never forget the days (that/which) we spent with him.③尽管先行词是指时间的名词，关系词在句中作主语，宾语，但非限制性定语从句只能选which。
Wednesday is the day, which comes before Thursday.④one 作替代词，代替前面表示时间的名词，其后的that/which往往省略。
That was an exciting moment, one I will remember forever.⑤time作先行词，前面有序数词或last时，只能选that。
Is this the third time that you have been late for school this week?11.why①当先行词是指表示原因的名词reason时，如果关系副词作状语，选why，why=forwhich.This is the reason why I didn’t attend the meeting yesterday.②当先行词是表示原因的名词reason时，如果关系副词在句中作宾语，选that/which,也可省略。
My parents didn’t believe the reason (that/ which) I give him.七．介词+which/whom1.介词+which/whom①介词的选择根据下面四种情况a.根据定语从句中的谓语动词Who is the person with whom you shook hands just now?b.根据定语从句中的形容词In learning English, he had two things about which he was not sure.c.根据定语从句所修饰的先行词This is the bike by which I go to school.d.根据句意。
This is the train on which he works.②如果关系词指人，选whom，如果关系词指物，选which。
2.不定代词+of+which/whom常用的不定代词有：both, neither, either(两者之一)，all, none, many, most, some, anyMr. Li has two sons, both of whom are college students.There are 10.000 books in this library, most of which are interesting.3.数词，分词，百分数+of+which/whomThere are 50 students in our class, two thirds of whom are girls.4.the+名词+of+which=whose+名词He has just bought a magazine, the cover of which (=whose cover) is missing.5.介词+whose+名词This is our school teaching building, on whose top there is a red flag.八．非限制性定语从句如果主语和定语从句之间有个逗号，它就是非限制性定语从句。
引导非限制性的定语从句的关系词有：which，who, when, where, why, whom, whose.九．分隔性的定语从句有时定语从句和先行词之间被其他词隔开，把这种从句叫分隔性的定语从句。