位置：先行词之后 　　例：Those who are willing to attend the party , sign your name please. 　　定语从句是由关系代词或关系副词引导的从句,其作用是作定语修饰主句的某个名词性成分,相当于形容词,所以又称为形容词性从句,一般紧跟在它所修饰的先行词后面. 　　引导定语从句的关联词称为关系词,关系词有关系代词和关系副词.关系代词有that, which, who, whom, whose, as等,绝对没有“what”；关系副词有where, when, why等.关系词常有3个作用： 　　①连接作用,引导定语从句. 　　②代替先行词. 　　③在定语从句中担当一个成分. 　　注：关系代词有主语、宾语之分.一般whom作为宾语.关系代词在从句中作主语,宾语,表语,定语等,关系副词在从句中作地点状语（where）时间状语（when）,原因状语（why）.
定语
　　定语用来限定、修饰名词或代词,是对名词或代词起修饰、限定作用的词、短语（动词不定式短语、动名词表示的）汉语中常用“……的”表示.主要由形容词担任,此外,名词、代词、数词、分词、副词、不定式以及介词短语也可以来担任,也可以由一个句子来担任.单词作定语时通常放在它所修饰的词之前,作前置定语.短语、从句作定语时则放在所修饰的词之后,作后置定语. 　　被定语从句修饰的名词、代词称为先行词.如“The man”、“The book”.
编辑本段关系代词引导的定语从句举例
　　关系代词所代替的先行词是人或物的名词或代词,并在从句中充当主语、宾语、定语等成分.关系代词在定语从句中作主词保持一致.
1,who, whom, that
　　这些词代替指人,“whom”作宾语指人,“that”既可作主语又可作宾语（作宾语可以省略）,可以指人也可以指物.在从句中所起作用如下： 　　（1）Is he the man who/that wants to see you? 他是那个想见你的男人吗?（who/that在从句中作主语） 　　（2）He is the man whom/ that I saw yesterday. 他就是我昨天见的那个人.（whom/that在从句中作宾语） 　　（3）The man whom you spoke to just now is our English teacher. 你刚刚说话的那个男人是我们的英语老师.
2,Whose 用来指人或物
　　(只用作定语, 等,作宾语时可以省略）,例如： 　　（1）Prosperitywhich / that had neppearsin te. 农村出现了前所未有的繁荣.（which / that在从句中作主语） 　　（2）The package (which / that) you are carryingis about to come unwrapped.你拿那个包裹快要散开了.（which / that在从句中作宾语）
whose
　　“whose”表示谁（可以为人也可以为物）的（东西） 　　例：A child whose parents are dead is called an arphan.双亲都死了的孩子叫做孤儿.（“whose”表示那个孩子的双亲） 　　He lives in a room whose window faces south.他住的那个房子的窗户是朝南的.（“whose”表示那个房子的窗户） 　　关系代词：在句中作主语、宾语或定语. 　　1. that既可代表事物也可代表人,“which”代表事物；它们在从句中作主语或宾语,“that”在从句中作宾语时常可省略关系词,“which”在从省略.[eg：This is the book （which）you want.] 　　2. 不及物动词+介词”的介词的宾语代词“wh”放在它原来的位置. 　　3. 代表物时多这时的that常被省略； 　　c）被形容词最高级修饰时；既有人又有物时； 　　e）整个句中前面已有“which”,“wh”行 　　关系副词：在句中作状语 　　关系副词=介词+关系代词 　　why=for which 　　where=in/ at/ on which（介词同先行词搭配） 　　when=during/ on/ in/…… which（介词同先行词搭配） 　　1. “where”是关系代词,当然也不用“that”引导. 　　By the time when you arrived in London, we had stayed there for two weeks. 到你到达伦敦的时候,我们在那里已经待了两个星期. 　　I still remember the her. 我仍然记得我第一次见到她. 　　Each time when he goes to business trip, he brings a lot of living necessities, such as towels, soap, toothbrush etc. 他每次出差都带来了生活必需品,如毛巾,肥皂,牙刷等其他东西. 　　3. 当从句的逻辑主语是some, any, no, somebody, anybody, nobody, something, anything, everything或nothing时,常用“there is”开头. 　　There is somebody here who wants to talk to you. 这里有人要和你说话. 　　分作进一步说明,通常是引导词和先行词之间用逗号隔开,将从句拿掉后其他部分仍可成立.
编辑本段非限制性定语从句
　　意义： 　　非限制性定语从句起补充说明作用,缺少也不会影响全句的理解.在非限制性定语从句的前面往往有逗号隔开,如若将非a lovely garden.　我去年买的的房子带着个漂亮的花园. 　　This novel, which I have read three times, is very touching. 这本我已经读过三遍的小说很感人. 　　3. 非限定性定语从句可将整个主句作为先行词, 对其进行修饰, 这时从句谓语动词要用第三人称单数,例如： 　　He seems not to have grasped what I meant, which greatly upsets me.他似乎没抓住我的意思,这使我心烦. 　　Liquid water changes to vapor, which is called evaporation. 液态水变为蒸汽,这就叫做蒸发. 　　4. 有时as也可用作关系 　　5. 在非限定性定语从句中,不能用关在从句中做主语 　　（1）The boys who are playing football are from Class One. 在踢足球的男孩们是一班的. 　　（2）Yesterday I helped an old man who lost his way. 昨天,我帮助了一个迷路的老人.
whom指人
　　注意：关系代词“whom”在口语和非正式语体中常用“who”代替,可省略. 　　如果在从句中做宾语,就用“whom”或“who”. 　　He is the man whom has an English book. 他就是那个有英语书的男人. 　　You just meet the person whom is my friend. 你刚刚见到的那个人就是我的朋友.
whose通常指人也可指物
　　在定语从句中做定语,表所有. 　　（1）He has a friend whose father is a doctor. 他有一个朋友的父亲是医生. 　　（2）I once lived in a house whose roof has fallen in.我曾经住在一座现在已经倒塌的房子中. 　　“whose”指物时通常以以下结构来代替： 　　（3）What is the color.Football isa game which is liked by most 　　颜色是什么.足球是大多数男孩都喜欢的游戏. 　　（4）This is the pen（which）he bought yesterday. 这是他昨天刚买的钢笔.
that指人时
　　相当于“who”或者“whom”；指物时,相当于“which”当前头有最高级序数词“all”不定代词时必须用“that”. 　　在定语从句中做主语、表语或者宾语,做宾语时可省略. 　　（5）The number of the people that/who come to visit the city each year rises one million. 每年来这座城市观光的游客数目上升了100万. 　　（6）Where is the man this morning? 今天早上这个男人在哪?
when指时间
　　在定语从句中做时间状语也可做连接词用. 　　（1）(1) I still remember the day when I first came to the school. (2) The time when we got together finally came.
why指原因
　　在定语从句中做原因状语. 　　（1）Please tell me the reason why you missed the plane. 　　（2）I don't know the reason why he lookswhen/in which he was going to school he began to know what he wanted when he grew up.
编辑本段介词和关系代词
　　1）介词后面的关系代词不能省略. 　　2）“that”前“Do you”作介词的宾语,且可以省略.例如： 　　（1）The school（that/which）he once studied in is very famous.“that/which”可以省略. 　　= The school i which hied is very famous.“which”不可省略. 　　（2）Tomorrow I will bring here 用,如：look for, look after, take care of等. 　　T This is the watch which/that I am looking for.（T=正确） 　　F This is the watch for which I am looking.（F=错误） 　　2. 若介词放在关系代词前,关系代词指人时用“whom”,不可用“who”或者“that”；指物时用“which”,不能用“that”；关系代词是所有格时用“whose” 　　（1）The man with whom you talked is my friend.（T） 　　The man famous. 　　（2）I bought many books yesterday, three of which are written by Lu Xun.
关系代词
　　关系代词（一般情况下）“that”可用在从句做主语,谓动词的宾语,但是不能做介词的宾语. 　　“which”指物,在从句句中作主语； 　　“whom”在从句中作宾语； 　　“why”在从句中修语,先行词通常是“the reason”； 　　有时“why”也可用“for+which”代替. 　　例：A doctor who looks after people's health. 　　主语 谓语 先行词 定语从句修饰先行词
判断介词和关系代词
　　方法一： 用关系代词,还是关系副词完全取决于从句中的谓语动词.不及物动词后面无宾语,就必须要求用关系副词或者是介词加关系代词；而及物动词后接宾语,则要求用关系代词.例如：　This is the mountain village where I stayed last year.　 　　判断改错: 　　（错） This is the mountain village where I visited last year.　（错） I will never forget the days when I spent in the countryside.　（对） This is the mountain village (which) I visited last year.　（对） I'll never forget the days (which) I spent in the countryside.　 　　例. Is this the museum ____ the exhibition was held? 　　A. where　B. that　C. on which　D. the one 　　,解析： 主、谓、宾俱全,从句部分为句子的状语表地点,既可用副词where,又因 in the museum词组,可用介词in + which 引导地点状语.而此题中,介词on 用的不对,所以选A.　 　　关系词的选择依据在从句中所做的成分,先行词在从句中做主、宾语时,选择关系代词（who, whom, that, which, whose）； 　　先行词在从句中做状语时,应选择关系副词（“where”地点状语,“when”时间状语,“why”原因状语）.
编辑本段先行词和关系词
　　1）Whoever spits in public will be punished here.（“Whoever”可以用“anyone who”代替） 　　2）The parents will use what they have to send their son to technical school. （“what”可以用“all that”代替） 　　但这两句句子已经不是定语从句了,是名词性从句.因为定语从句一定要有先行词,而名词性从句没有.将“Whoever”、“what”分别用“Anyone who”、“all that”代替后,才是定语从句,先行词分别是“Anyone”、“all”.an invitation from her boss, ___came as a surprise. 　　A. it　B. that　C. which　D. he　 　　答案C. 　　此为非限定性从句,不能用“that”修饰,而用“which”、“it”和“he”都使后句成为句子,两个独立的句子不能单以逗号连接.况且选“he”句意不通. 　　2）The weather turned out to be very good, ___ was more than we could expect. 　　A. what　B. which　C. that　D. it　 　　答案B 　　英语语法上行不通. 　　3）It rained hard yesterday, ____ prevented me from going to the park. 　　A. that　B. which　C. as　D. it　 　　答案B　　 　　“as”和“which”在引导非限宾语.但不同之处主要有两点：　 　　（1）importance to me, as my own is. 　　在一定的语言环境里,有些名词可以具有形容词的性质.这些名词主要是那些表示人的身份、职业、状态的名词.值得一提的是,在这些具有形容词性质的名词之后,引导定语从句的关系代词不能用“who / whom”. 　　（2）动词短语先行成分. 　　这种动词短语既可是限定形式也可是非限定形式.如果是动态动词短语,它们在从句中就一般有限定或非限定形式的替代动词“do”和“as / which”一起代替.“do”可以出现,也可以不出现,但不能用其它动词代替. 　　（3）句子作先行成分. 　　这句子可以是整个主句也可以只是主句中的一个从句.有时是连续几个句子,有时甚至可以是一个完整的故事. 　　二、“as/which”特殊定语从句在句中的位置. 　　由于先行成分的构成成分”特殊定语从句在句中的位置有以下几种情况： 　　1. 形容词做先行成分时：形容质的which”特殊定语从句置于先行成分之后. 　　2. 动词词短语作先行成分时,“as / which”特殊定语从句置于先行成分之后.但是,当从句中含有表示主观意志的插入成分时,“as”特殊. 　　3. 句子作先行成分时：“as”特殊定语从句的位置较灵活,可以置于先行成分之前、之中或之后.但如果先行成分是直接引语,“as”特殊定“s”特殊定语从句与否定词的相对中则常用一些表示“合乎自然规律”、“众所周知”或“经常发生”等意义的词语,如natural, known to all, usual等. 　　3. 有无状语意要是方式状语意义,而“which”特殊定语从句则无状语意义.“as”特殊定四、关系代词“as”与“which”一词.如： 　　Freddie, as might be expected, was attending the conference. 　　1. “Which”作主语时,谓语动词不限,主动被动皆可,只是谓语动词为被动语态时助动词“be”省略. 　　2. “as”和“which”都可以在特殊定语从句中宾语. 　　3. “as”和“which”在特殊从句中作补语.如： 　　We thought him a gentleman, as/which he could never be. 　　“as”特殊定语从句中可以主谓倒装,“which”从句中则不能主谓倒装. 　　如果先行成分不是主语补语或宾语补语,关系代词用“which”而不用“as”.如： 　　He talked like a native, which/as he hardly was. 　　4. “which”在特殊从定法 　　（1）不用that的情况　 　　（a）在引导非限定性定语从句时. 　　（错）The tree, which is four hundred years old, Is very famous here.　 　　（b）介词后不能用.　 　　We depend on the land from which we get our food.　 　　We depend on the land that/which we get our food from. 　　（2）只能用“that”作为定语如“last,just”修饰时,只用“that”.　 　　（d）先行词为序数词、数容词,又有物时. 　　（f）先行词指物,在主句中作是“the way”或“the reason”时,“that”可作关系副词,也可省略 　　（h）主句的主语是疑问词“who /which”时,避免重复要用“that”． 　　举例： 　　Is this the book that you borrowed in the library? 　　这是你在图书馆借的书吗? 　　Who that break the window should be punished． 　　谁打碎了窗户.　 　　All that is needed is a supply of oil. 　　所需的everything that he had stolen to the police.　 　　那贼最终把偷的全部东西交给了警察. 　　“that”必用 　　1、先行词是最高级或被最高级修饰. 　　2、是序数词或被序数词修饰. 　　3、不定代词指物. 　　5、被“only”、“the every”、“no”、“one of”等修饰 　　6、主句有“which”、“who”、“whom” 　　7、“there be”句型中 　　8、如果有两个从句,其中一个关系代词已用了“which”,另一个关系代词宜用“that” 　　9、先行词在主句中作表语,或者关系代词本身作从句的表语是宜用“that” 　　“that”在作宾语时可省略. 　　10、不是任何时刻关系词作主语宾语是能用“that”难点分析“you”注意1：the only,the same,the last ,any,little等修饰时(1) This is the very good dictionary that I want to buy,(2) After the fire in his house, the old car is the only thing that he owned.当先行词指人时,偶尔也可以用who(3) Wang Hua is the only person in our school who will attend the meeting?5、当先行词前面有who, which等疑问代词时(1) Who is the man that is standing there?(2) Which is the T-shirt that fits me most?6、当先行词既有人,也有动物或者物体时Can you remember the scientist and his theory that we have learned?7.当关系代词在定语从句中做表语The village is no longer the one that it used to be 10 years ago.8.当在which引导的定语从句as和which引导非限制性定语从句,有相同之处也有不同之处.具 a developing country.(2) He is from the south, as we can see from his accent.(3) John, as you know, is a famous writer.(4) He has been to Paris more than several times, which I don’t believe.注意：当主句和从句存在逻辑上的因果关系时,常用which.(5) Tom was always late for school, which made his teacher angry.3、当先行词受such, the same修饰时,常用as(1) I have never heard such a story as he tells.(2) He is not such a fool as he looks.(3) This is the same book as I lost last week.注意：当先行词由the same修饰时,偶尔也用that引导定语从句,但是和由as所引导的定语从句意思不同(4) She wore the same dress that she wore at Mary’s wedding. 她穿着她注意：定语从句such…as …与结果状语从句such… that…的区别：as在所引导的定语从句中作主语,宾语；that在结果状语从句中不做成分　(6)He has such a good laptop as I want to buy. 　　（7）He idea.（but= who don’t） 　　（五）区分定语从句和同位语从句 　　1、定语从句修饰先行词,它和先行词是修饰关系； 　　同位语从句说明先行词的具体内容,是补充说明的关系 　　（1）The planeis clear. 同位语从句 　　2、定语从句由关系代for advice. 　　（3）The fact that the moon moves around the earth is known to all. 　　（4）The fact is that the moon moves around the earth. 　　[定语从句]介词+关系词 　　1）介词后面的关系副词不能省略. 　　2）“that”前不能有介词. 　　3）某些在从句中充当时间,地点或原因状语的"介词+关系词"结构可以同关系副词“when”和“where”互换.例如： 　　This is the house in which I lived two years ago. 这是我两年前住过的房子. 　　This is the house where I lived two years ago. 　　Do you remember the day on which you joined our club? 还记得你加入我们俱乐部的那一天吗? 　　Do you remember the day when you joined our club?