新托福考试虽然不再对语法进行单独的考查，但实际上是把语法知识渗透到了听、说、读、写的各个方面。下面小编为大家讲解托福核心语法之定语从句，一起来学习一下吧。
课程目录：
1. 定语从句概述
2. 定语从句——托福阅读
3. 定语从句——托福写作
1. 定语从句概述
A. 定语从句：起修饰作用的从句
B. 先行词：名词/代词/动名词短语/句子
C. 关系代词：引导定语从句
D. 关系副词：引导定语从句
关系代词的用法：
(1)that和which都可以指物，但以下五种情况只能用that不能用which：
①当先行词中有人又有物时。如：
I really have no idea about the shopping center and the great scientist that they are talking about.
②当先行词为不定代词one, few, little, no, some, any, everything, nothing, nobody, none等或者被这些不定代词修饰时。如：
This is all that I want from the school.
All the great scientific discoveries that the physicist has made inspire the students.
③当先行词被only，just，very，right，last等修饰时。如：
This is the very book that I am looking for these days.
④当先行词被形容词最高级修饰时。如：
The TV tower is the highest building that has been built in this city.
⑤当先行词被序数词修饰时。如：
The first lesson that I learned when I was in elementary school will never be forgotten.
(2)that和which都可以指人，但下面两种情况，多用who：
①先行词为all，anyone，one，ones等时。如：
All who heard the news were excited.
②先行词为those或people时。如：
Those who want to attend the meeting please sign your names here.
关系副词的用法：
关系副词=介词+关系代词
when=in/at/on…+which
why=for+which
where=at/in/on…+which
例句：
The reason why/ for which he refused the invitation to the ceremony is not clear.
From the year when/in which he was going to school he began to know what he wanted when he grew up.
A marine environment is the place where the first whale lived in/in which the first whale lived.
定语从句的分类
定语从句可分为限制性定语从句和非限制性定语从句，两者的区别在于：
例：They overcame all the difficulties and completed the project two months ahead of time, which was something we had not expected.
2. 定语从句——托福阅读
句子简化题
例1：Many ecologists now think that the relative long-term stability of climax communities comes not from diversity but from the “patchiness” of the environment, an environment that varies from place to place supports more kinds of organisms than environment that is uniform.
这句话的主干是“Many ecologists now think that…”，句子中包含两个定语从句，一个是“…that varies from place to place”，一个是“…that is uniform”。简化后的句子是“A patchy environment is thought to stability because it is able to support a wide variety of organisms .”。
例2：For example, people who believe that aggression is necessary and justified-as during wartime- are likely to act aggressively, whereas people who believe that a particular war or act of aggression is unjust, or who think that aggression is never justified, are less likely to behave aggressively.
这句话中包含两个定语从句，一个是“people who believe that aggression is necessary and justified…”，一个是“people who believe that a particular war or act of aggression is unjust， or who think…”。这里是在比较两种人：一种人认为攻击性是有必要的，另外一种人认为攻击性是不正义的，前者比后者更容易表现出攻击性。因此，简化后的句子就成了“People who believe that aggression is necessary and justified are more likely to act aggressively than those who believe differently. ”。
3. 定语从句——托福写作
托福写作中使用定语从句要注意两点：善于使用定语从句;正确使用定语从句。
例1：My grandmother always tells me some old sayings related to staying healthy, and most of these old sayings have been proved to be famous dictums.
这句话是一个并列句，用连接词“and”将前后两句话连接了起来，不过这样会显得很累赘，如果我们使用一个定语从句，那么句子就会变得更简洁，如：“My grandmother always tells me some old sayings related to staying healthy, most of which have been proved to be famous dictums”。
例2：The young people of the big cities in China always feel more stressful because both the housing prices and the medical expenses are unaffordable.
上面这句话同样可以用一个定语从句让句子变得更高级。如：“The young people live in the big cities of China where both the housing prices and the medical expenses are unaffordable, always feel stressful.”。
考生在托福写作中使用定语从句时可能会出现以下几种错误：
例1：For my part, I believe that people have true friendship which we cannot measure it using money.
这句话包含一个定语从句，但是代词“it”在这里使用错误：因为前面已经出现了关系代词，代指的就是“true friendship”，不必再使用代词“it”了，它们所指代的内容是一样的。因此，这句话可以改成“For my part, I believe that people have true friendship which cannot be measured using money.”。
例2：People who learn ideas and concepts will be more knowledgeable than those that only study facts.
这句话中包含两个定语从句，第二个从句中的关系代词“that”使用错误，因为如果先行词是“those”指代人，那么关系代词只能用“who”，不能用“that”，因此这句话应该改成“People who learn ideas and concepts will be knowledgeable than those who only study facts.”。
以上就是托福核心语法之定语从句的用法，希望能给大家的学习带来帮助。最后，小编祝愿各位考生在托福考试中取得好成绩!
您还可能关注：
