定语从句

定语从句

1.定语从句的分类

定语从句有限制性和非限制性两种:
限制性定语从句是先行词不可缺少的部分，去掉它主句意思往往不明确;
非限制性定语从句是先行词的附加说明，去掉了也不会影响主句的意思，它与主句之间通常用逗号分开。
例:This is the house which we bought last month. (限制性)这是我们上个月买的房子。
The house, which we bought last month, is very nice. (非限制性)我们上个月买的房子很漂亮。

(1)当先行词是专有名词或有物主代词和指示代词所修饰时，其后的定语从句通常是非限制性的。
例: Charles Smith, who was my former teacher, retired last year.查尔斯·史密斯，我以前的老师，去年退休了。
My house, which I bought last year, has got a lovely garden.我去年买的房子有一个可爱的花园。
This novel小说, which I have read three times, is very touching.这本小说我读了三遍，很感人。
(2)非限制性定语从句还能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: He seems not to have grasped what I meant, which这 greatly. 他似乎没有理解我的意思
Liquid water changes to vapor, which这 is called evaporation.液态水变成蒸汽，这被称为蒸发。

2.定语从句的关系词

关系代词引导的定语从句
关系代词所代替的先行词是人或物的名词或代词，并在句中充当主语、宾语、定语等成分。关系代词在定语从句中作主语时，从句谓语动词的人称和数要和先行词保持一致。
先行词就是定语从句前面那个被修饰的词，通常是个名词或代词
(1)who,whom,that这些词代替的先行词是人的名词或代词，在从句中所起作用如下:
例: Is he the man who / that wants to see you?他就是那个想见你的人吗？
He is the man (who/ whom/ that) I saw yesterday.他就是我昨天见到的那个人。
(2) 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。
例: A prosperity which/that had never been seen before appeared in the countryside农村.农村出现了前所未有的繁荣。
The package (which/that) you are carrying is about to come unwrapped.你携带的包裹即将被拆开。
(3)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: They rushed over to help the man whose car had broken down.他们冲过去帮助那个汽车抛锚的人。
Please pass me the book whose (of which) cover is green.请把封面是绿色的那本书递给我。
(4)as
1、与such，the same...as和as连用，意为“像......一样的，同......一类的”。
例: I live in the same place as Tom does.我和汤姆住在同一个地方。
He' s not such a fool as he looks.他不像看上去那么傻。
He smokes as expensive昂贵的 a cigarette as he can afford买得起.他抽得起最贵的烟。
2、单独用作关系代词，意为“正如”，可放在主句之前、之后或中间，且主从句之间一般要用逗号隔开。
例: As we know, smoking is harmful to one's health.正如我们知道的，吸烟有害健康。
As is known, smoking is harmful有害的 to one's health.众所周知，吸烟有害健康。

关系副词引导的定语从句

关系副词可代替的先行词是时间、地点或理由的名词，在从句中作状语。
(1) when, where, why
关系副词when，where,why的含义相当于“介词+which”结构，因此常常和“介词+which”结构交替使用。
例: There are occasions…的时候 when (on which) one must yield.有时人必须得让步
Beijing is the place where (in which)I was born.北京是我出生的地方。
Is this the reason why (for which) he refused拒绝 our offer?这就是他拒绝我们报价的原因吗？

“介词+关系词”引导的定语从句
(1)介词后面的关系词不能省略。
(2)“介词+关系词”引导定语从句时，若指人，则用介词+whom;若指物，则用介词+which。
例:My cousin is a person with whom I can discuss讨论 my homework.我表哥是一个可以和我讨论作业的人。
The West Lake, for which Hangzhou is famous, is a beautiful place.杭州以西湖而闻名，西湖是一个美丽的地方。

关系代词that的用法
1.不用that的情况:
(1)在引导非限制性定语从句时。
例: The tree, which is four hundred years old, is very famous here.这棵有四百年历史的树在这里很有名。
(2)介词后不能用。
例: 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作为定语从句关系代词的情况:
(1)先行词为all,everything,anything,nothing,little,much等不定代词时;
(2)先行词被all,any,every,each, much, little, no,some,few等修饰时;
(3)先行词有形容词最高级和序数词修饰时;
(4)先行词既指人又指物时;
(5)先行词被the only，the very修饰时;
(6)句中已经有who或which，为了避免重复时。
例: All that is needed is a supply of oil.
Finally, the thief handed everything that he had stolen to the police.

1. Is this the factory （C） you visited参观 the other day?
   A.what B.where C.that D.when
2. These are the pictures图片 of the hotel （A） we held ourannual meetings.
   A. where B.which C.that D.when

3.（A）is known to the world, Mark Twain was a great American writer.众所周知，马克·吐温是一位伟大的美国作家。
A.As B.that C.That D.what

4. These apple trees,（A）I planted three years ago, have not borne any fruit.我三年前种的这些苹果树还没有结果。
   A.which B.Once C.when D. It