定语从句作为初中英语的难点，在语篇阅读中对定语从句的考查必不可少。因此掌握定语从句的简单用法是非常有必要的。
在做此类试题时，首先确定先行词是指物还是指人，指人就从that, who, whose, whom中选择；指物就从that, which中选择。然后再根据关系词在从句中所作的成分来确定到底应该用哪一个关系词。
1、定语从句概述
在复合句中作定语的从句叫定语从句。被定语从句所修饰的词叫先行词,通常位于定语从句之前。引导定语从句的是关系代词that,which,who,whose,whom和关系副词when,where,why。关系代词或关系副词既起连接作用,又充当从句中的一个成分。
2、关系代词的用法
一般情况下,that既可指人又可指物,可以代替who,whom和which,在从句中作主语、表语或宾语;which指物,在从句中作主语、表语或宾语;who在从句中作主语、表语或宾语;whom在从句中作宾语;whose在从句中作定语。
A doctor is a person who looks after a patient.
先行词 主语 谓语 宾语
句意:医生就是照顾病人的人。
1.下列情况下,先行词指物时,只能用that引导,不能用which引导:
(1)当先行词是all,little,much,none,everything,anything,nothing等代词时。
Is there anything that you don’t understand?你有什么不懂的地方吗?
Tom told his mother all that had happened.汤姆把发生的一切都告诉了他的妈妈。
(2)当先行词前面有the only,the very,the last等修饰时。
This is the only book that I can find.这是我能找到的唯一的一本书。
(3)当序数词或形容词最高级修饰先行词时。
This is the best book that I have ever read.这是我读过的最好的书。
(4)当主句是以特殊疑问词which开头的特殊疑问句时。
Which is the hotel that you like best?哪个是你最喜欢的旅馆?
2.关系代词的省略
一般情况下,关系代词作宾语时可以省略,但关系代词which,whom在从句中作介词的宾语并且介词位于关系代词之前时,不能省略。
I’ll never forget the day on which I joined the club.我永远不会忘记我加入俱乐部的那一天。
注意:that,which,who在从句中作主语时,不能省略。
Who is the boy that is talking with our teacher?正在和我们老师谈话的那个男孩是谁?
3、关系副词的用法
This is the factory where my father works.
先行词 地点状语 主语 谓语
句意:这就是我爸爸工作的那个工厂。
1.when表示时间,在定语从句中作时间状语。
I still remember the year when you graduated from No.8 Middle School.我依然记得你从八中毕业的那一年。
2.why表示原因,在定语从句中作原因状语,其先行词是表示原因的reason一词。
We don’t know the reason why he was late for school.我们不知道他为什么上学迟到。
3.where表示地点,在定语从句中作地点状语。
That is the school where I studied three years ago.那就是我三年前就读的学校。
4、定语从句解题技巧
Running Man is a very relaxing TV program which is popular among the young people.
主句：Running Man is a very relaxing TV program
从句：which is popular among the young people
先行词：TV program
关系代词：which
因此,如果确定是考查定语从句,我们就可以排除不是关系代词或关系副词的选项，如：what。
在此过程中要掌握“三看”原则。
（1）一看指人还是物
先行词指人：that,who, whose, whom
先行词指物：that, which, whose
（2）二看句中作何用
主语 who(人), which（物）, that（人/物）
宾语 who/whom(人), which（物）, that（人/物）
定语 whose（人/物）
状语 where(地点), when（时间）, why（原因）
如：My brother likes the stories ______ were written by Mark Twain because they are often humorous. 先行词(the stories)指物,关系词在从句中作主语,可用关系代词which/that。
如：He is the boy ______ I talked with just now. 先行词（the boy）指人,关系词在从句中作宾语,可用关系代词whom/who/that/不填。
如：What‘s the name of the girl ______ father is a doctor？ 先行词(the girl)指人,关系词在从句中作定语,可用关系代词whose。
如：I still remember the day ________ our new school was built. 从句中不缺成分,先行词（the day）指时间,关系词在从句中作状语,可用关系副词when。
（3）看是否是特殊情况：
关系词只能用that的几种情况
①当先行词是all, little, much, none, everything, anything, nothing等不定代词时。如：
Tom told his mother all that had happened. 汤姆把全部情况告诉了他的妈妈。
②当先行词前面有the only, the very, the last等修饰时。如：
This is the only book that I can find. 这就是我能找到的唯一一本书。
③当序数词或形容词最高级修饰先行词时。如：
The tallest player that plays football for our team is from Shanghai. 为我们足球队踢足球的那个最高的运动员来自上海。
④当先行词既有人又有物时。如：
Let’s talk about the people and the things that we can remember. 让我们谈论我们能够记起的人和事。
关系词只能用which的几种情况:
①关系代词放在介词之后。如：
This is the factory in which we once worked. 这就是我们曾经工作过的工厂。
②非限制性定语从句中。如：
This is a famous book, which was written by Lu Xun. 这是鲁迅写的一本有名的书。
③that， those作主语时。如：
Those which are on the desk are English books. 桌子上的那些是英语书。
用who而不用that的情况:
①当先行词为people和those时，只能用who。如：
Those who want to go there come here please. 那些想去那儿的人请来这边。
②当先行词为one, ones, anyone, everyone, none, all(指人)时，只能用who。如：
Anyone who is against us is our enemy. 任何反对我们的人就是我们的敌人。
③先行词指人，而关系代词在从句中作主语时，一般多用who。如：
The man who came here yesterday said he would come again in a few days. 昨天来这儿的那个人说过几天他会再来。
