定语从句专项讲解与练习定语从句的定义：从句作定语，修饰名词、代词，这样的从句叫定语从句。
定语从句所修饰的词叫先行词。
定语从句作定语放在先行词的前面。
如果要表达:我喜欢那个漂亮的女孩。
I love the pretty girl.如果要表达：那个喜欢我的女孩。
只能借助于定语从句the girl who loves me.其中the girl即为定语从句的先行词，而who即为定语从句的关系词。
指人：who、whom关系代词指物：which、as（作主宾表）指人和物:that,whose关系词表时间：when关系副词表地点：where（作状）表原因：why1、who指人，who在从句中当主语。
He who has not reached the Great Wall isn’t a true man. 不到长城非好汉。
The teacher ___________spoke at the meeting just now is having a rest in his office.中文意思：____________________________________________________________________❖作主语时不能省略，作宾语时可省略。
2、whom指人，是who的宾格形式，在从句中作宾语，前面没有介词时，可用who/that来代替，也可省略。
The girl ___________________ I like isn’t here now.中文意思：____________________________________________________________________The doctor with ________________she went to the United States last month is very famous.中文意思：____________________________________________________________________The person ___________________ you met yesterday is our Chinese teacher.中文意思：____________________________________________________________________3、whose指“谁的”，或“某物的”，在从句中作修饰词。
whose和它所修饰的名词在定语从句中可作主语及动词或介词的宾语。
The girl ___________father is a doctor is our classmate.You’re the only one ____________ advice he might listen to.中文意思：____________________________________________________________________I’d like a room _______________window looks out over the sea.中文意思：____________________________________________________________________4、that在从句中作主语或宾语，既可以指人又可以指物；作宾语时可以省略。
She is the very person (that) I want to see at once.中文意思：____________________________________________________________________A plane is a machine_____________ can fly.中文意思：____________________________________________________________________5、which在从句中作主语或是宾语，只能指物；West Lake ______________lies in Hangzhou is one of the most famous lakes in China.中文意思：____________________________________________________________________The coat (___________________) I put on the desk is black.6、as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。
e.g. 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 .※但在以下两种情况下有区别：. as从句可位于句首(或主句前) , 而which从句只能在主句后。
e.g. ____ is often the case , we have worked out the production plan .A . WhichB . WhenC . WhatD . Asthat, which可以在从句中当主语或宾语，当宾语时可以省略。
whom在从句中是当宾语的，也可以省略。
但是，当以上关系词前面有介词时，就不能省略。
A）指人时who, whom, that 这些词代替的先行词是人的名词或代词，把以下两个句子合并成一句：I thank the woman.The woman helps me a lot.I thank the woman who (that)helps me a lot.（主语）The man was Jone .I saw him.The man (who whom that) I saw was jone.(作宾语)She was the woman .I told you about her.She was the woman (who whom that) I told you about .(做介词宾语) /She was the woman about whom I told you.(介词后只能用宾格)B）指物时which, that它们所代替的先行词是事物的名词或代词，在从句中可作主语、宾语等，把以下两个句子合并成一句：A prosperity appears in the countryside.A prosperity had never been seen before .A prosperity which / that had never been seen before appears in the countryside. 农村出现了前所未有的繁荣。
（which / that在句中作主语）1.Where is the book (which/that) I bought last week?A. whichB. thatC. whoD. as2.The place _______interested me most was the Children's Palace.A. whichB. whereC. whatD. in whichC) Whose 用来指人或物，(只用作定语, 若指物，它还可以同of which互换）,例如：They rushed over to help the man. His car had broken down.They rushed over to help the man whose car had broken down.那人车坏了，大家都跑过去帮忙。
It there anyone in your class ______family is in the country?A.whoB. who'sC. whichD. whose●that与which的区分A）指物或人时宜用that 的情况：❖先行词是不定代词all, everything, nothing, anything, much, little, few等时Is there anything (that) you don’t understand?All that can be done has been done.❖先行词被all, every, any, no, little, much等修饰时，I want to read all the books ___________ were written by Lu Xun.❖先行词被序数词及形容词最高级修饰时This is the best book (___________) I have ever read.This is one of the best films _______________I have ever seen.This is the best________________ can be done now.❖先行词被the only, the very, the last, the same修饰时，如果是人时，可以用who/whom来代替。
He is the only person___________________can help you out.中文意思：____________________________________________________________________This is one of the very book that I am looking for.中文意思：____________________________________________________________________❖当先行词既指人又指物时。
We are talking about the people and the things (____________) we have visited in this country.中文意思：我们正在谈论在这个国家所见过的人和事。
❖关系代词作定语从句中be的表语时，that可以省略。
The city is no longer the one (that) it used to be.Mary is no longer the girl that she used to be.❖主句是以who, what, which开头的特殊问句时。