在句子中起名词作用的句子叫名词从句 (Noun Clauses）。 名词从句的功能相当于名词词组, 它在复合句中能担任主语、宾语、表语、同位语、介词宾语等，因此根据它在句中不同的语法功能，名词从句又可分别称为主语从句、宾语从句、表语从句和同位语从句。
17.1 引导名词性从句的连接词
引导名词性从句的连接词可分为三类：
连接词：that,whether,if 不充当从句的任何成分）
连接代词：what, whatever, who, whoever, whom,
whose, which.
连接副词：when, where, how, why
不可省略的连词：
1. 介词后的连词
2. 引导主语从句和同位语从句的连词不可省略。
That she was chosen made us very happy.
We heard the news that our team had won.
比较：whether与if 均为"是否"的意思。 但在下列情况下，whether 不能被if 取代：
1. whether引导主语从句并在句首
2. 引导表语从句
3. whether从句作介词宾语
4. 从句后有"or not"
Whether he will come is not clear.
大部分连接词引导的主语从句都可以置于句末，用 it充当形式主语。
It is not important who will go.
It is still unknown which team will win the match.
17.2 名词性that-从句
1）由从属连词that引导的从句叫做名词性that-从句。 That只起连接主句和从句的作用，在从句中不担任任何成分，本身也没有词义。名词性that-从句在句中能充当主 语、宾语、表语、同位语和形容词宾语，例如：
主语：That he is still alive is sheer luck. 他还活着全靠运气。
宾语：John said that he was leaving for London on Wednesday. 约翰说他星期三要到伦敦去。
表语：The fact is that he has not been seen recently. 事实是近来谁也没有见过他。
同位语：The fact that he has not been seen recently disturbs everyone in his office.
近来谁也没有见过他，这一事实令办公室所有的人不安。
形容词宾语：I am glad that you are satisfied with your job.
你对工作满意我感到很高兴。
2）That- 从句作主语通常用it作先行词，而将that-从句置于句末，例如：
It is quite clear that the whole project is doomed to failure. 很清楚，整个计划注定要失败。
It's a pity that you should have to leave. 你非走不可真是件憾事。
用it作形式主语的that-从句有以下四种不同的搭配关系：
a. It + be +形容词+ that-从句
It is necessary that… 有必要……
It is important that… 重要的是……
It is obvious that… 很明显……
b. It + be + -ed 分词+ that-从句
It is believed that… 人们相信……
It is known to all that… 从所周知……
It has been decided that… 已决定……
c. It + be +名词+ that-从句
It is common knowledge that… ……是常识
It is a surprise that… 令人惊奇的是……
It is a fact that… 事实是……
d. It +不及物动词+ that-分句
It appears that… 似乎……
It happens that… 碰巧……
It occurred to me that… 我突然想起……17.3 名词性wh-从句
1）由wh-词引导的名词从句叫做名词性wh-从句。Wh-词包括who, whom,. whose, whoever, what, whatever, which, whichever等连接代词和where, when, how, why等连接副词。Wh-从句的语法功能除了和that-从句一样外，还可充当介词宾语、宾语补语和间接宾语等，例如：
主语： How the book will sell depends on its author. 书销售如何取决于作者本人。
直接宾语：In one's own home one can do what one likes. 在自己家里可以随心所欲。
间接宾语：The club will give whoever wins a prize.
俱乐部将给得胜者设奖。
表语： My question is who will take over president of the Foundation. 我的问题是谁将接任该基金会主席职位。
宾语补足语：She will name him whatever she wants to. 她高兴给他起什么名字就取什么名字。
同位语： I have no idea when he will return.
我不知道他什么时候回来。
形容词宾语：I'm not sure why she refused their invitation. 我尚不能肯定她为什么拒绝他们的邀请。
介词宾语： That depends on where we shall go.
那取决于我们去哪儿。
2）Wh-从句作主语也常用先行词it做形式主语，而将wh-从句置于句末，例如：
It is not yet decided who will do that job.
还没决定谁做这项工作。
It remains unknown when they are going to get married. 他们何时结婚依然不明。
17.4 if, whether引导的名词从句
1）yes-no型疑问从句
从属连词if, whether引导的名词从句是由一般疑问句或选择疑问转化而来的，因此也分别被称为yes-no 型疑问句从句和选择型疑问从句，其功能和wh-从句的功能相同， 例如：
主语：Whether the plan is feasible remains to be proved. 这一计划是否可行还有等证实。
宾语：Let us know whether / if you can finish the article before Friday. 请让我们知道你是否能在星期五以前把文章写完。
表语：The point is whether we should lend him the money. 问题在于我们是否应该借钱给他。
同位语：They are investigating the question whether the man is trustworthy. 他们调查他是否值得信赖。
形容词宾语： She's doubtful whether we shall be able to come. 她怀疑我们是否能够前来。
介词宾语： I worry about whether he can pass through the crisis of his illness. 我担心他是否能度过疾病的危险期。
2）选择性疑问从句
选择性疑问从句由关联词if/whether…or或whethe…or not构成，例如：
Please tell me whether / if they are Swedish or Danish. 请告诉我他们是瑞典人还是丹麦人。
I don't care whether you like the plan or not.我不在乎你是否喜欢该计划。
定语从句 (The Attributive Clause)
关键词
先行词·成分·动词性质2. I spent five days with Jim in summer camp, and
I won’t forget it. 定语从句(The Attributive Clause)
一．概念理解：
在复合句(包括主句和从句)中，修饰主句某一
名词或代词的从句叫定语从句(起形容词作
用，作定语；也可称之为形容词性从句)。
注意：引导词可分为两类：
关系代词：
who, whom, whose, that, which
(what=that which不能引导定语从句)
关系副词：
when, where, why
(how不用来引导定语从句，而用that/in which)注意：
定语从句前必须有先行词 (作主语、宾语、表
语或补足语)，否则就不没有说明或修饰的
中心内容。
2. 关系代词和关系副词连接先行词和定语从句，
起联系作用，同时在定语从句中担任一定的
句子成分（但翻译时不译出来）。
二．关系代词及其用法：1. 根据先行词确定关系代词
使用关系代词，完全取决于先行词的性质(人或
事物)、在从句中担任的成分和其人称、格和数
I want to buy the books that / which were written by LuXun.
说明：
先行词是books<物>，而且关系代词在从句中担任主语，所以用主格形式which或that；同时，先行词是复数，定语从句中的谓语动词须与之在人称和数上保持一致，所以要用were。
2. The man (who / whom / that) I talked to just now is LiYan.
说明：
先行词是man<人>，而且关系代词在从
句中担任宾语，所以用宾格形式who或
whom/that。
The pen (that / which) he gave me last week is black.
说明：
先行词是pen<物>，而且关系代词在从句
中担任宾语，所以用宾格形式which或that。
例：3. Do you know the man whose name is WangYu? Do you know the man the name of whom is WangYu?
说明：
先行词是man<人>，而且关系代词在从
句中担任定语，所以用所有格whose或
“名词+of whom”。
The book whose cover is black doesn’t belong to me. The book the cover of which is black doesn’t belong to me.
说明：
先行词是book<物>，而且关系代词在从
句中担任定语，所以用所有格whose或
“名词+of which”。
例：4. I have a lovely pet dog who /that has four short legs.
说明：
先行词是dog <动物，拟人化>，而且关
系代词在从句中担任主语，所以可用主
格形式who或that；同时，先行词是单数
第三人称，定语从句中谓语动词须与之
在人称和数上保持一致，所以要用has。
例：5. Have you found some information about that writer (that/which) you can use in your article?
说明：
先行词是information <事物>而非
writer<人>，而且关系代词在从句
中担任宾语，所以用宾格形式
which或that。
2). 确定和运用定语从句的思维步骤：
A. 找出先行词、关系代词和关系代词的人称、数和性。
关系代词在定语从句中代替主句中的先行词，它们
之间是一种“复指”关系。关系代词一般都跟在先行
词之后，定语从句中的谓语动词须与先行词的人称
和数保持统一。
B. 确定关系代词在从句中担任的成分，用以确定关系代词的格。
作主语：指人时，who比that常用；指事物时，that比which常用。(不能省略)
作宾语：指人时，that比whom常用；指事物时，that或which均可。(口语中常省略)
C. 根据实际情况确定定语从句的时态和语态，不受主句的影响。
3). 指代事物时只能用that而不用which的情况：
A.先行词all, any, one, none, few, little, much, something, anything, nothing, everything等不定代词时 B. 当先行词被all, any, few, little, no, just, some,
much, every等修饰时。 C. 当先行词被the only / very / right / same / last,
one of 等修饰时。 D.当先行词是序数词或被序数词或形容词最高级
修饰时。 E.当先行词既有人又有物时。注：(1). whom/which作介词的宾语时，介词一般可放在
whom/which之前，也可放在从句原来的位置
上；但是在含有介词的动词固定词组中，介词只
能放在原来的位置上，保持其意义的相对独立与
完整。(2). that引导定语从句时可以指人或物，在从句中
作主语或谓语动词的宾语，但不能放在介词后
面作介词的宾语。 4). 指代事物时只能用which而不用that的几种特殊
情况：5). 指代人时宜用who而不能用that情况：
A. 先行词是one, ones, anyone或具有泛指意义的he等时。
1. One who has nothing to fear for oneself dares to tell the
truth.
2. I will shoot anyone who moves.
3. He who does not reach the Great Wall is not a true man.
B. 当先行词是those时。
Those who want to go to the Great Wall sign up here.
God helps those who help themselves. C. 当先行词有较长的后置定语时。
例：I met a foreigner in the street who wished to
visit you.
D. 带有两个定语从句，其中前一个关系代词是
that时。
例：The boy that you met yesterday is the group
leader who studies hard.
E. 在there be开头的句子中。
例：There is an old man who wants to see you.
as引导的定语从句
一．as可以代替整个句子或一件事，引导非限制性
定语从句，在从句中作主语、宾语或表语，
意为“正如……，就像……，据……”；从句
位置可置于主句之前或之后，有时也可作为
插入语置于句中，一般用逗号和主句隔开。
1. As is well known, great changes have taken place in China. 2. The boy has as much progress as we had expected.
as 的这种用法常见于以下这些结构:
as we can see, as can be seen, as we know,
as is (well) known, as may be imagined,
as often happens, as has been said before,
as was mentioned above, as has been said
above，as anybody can see等.
1. She married him，which was unexpected. ＝She married him as (was) unexpected. 作主语，代替前面的句子；用which时was不可省。2. The earth , as we know, moves round the sun .
注意：
which在引导非限制性定语从句时，也有和as一样的功能，可以代替整个句子，但which只能用在主句之后。
在as所引导的非限制性定语从句中，如果运用的
是被动语态结构，be动词可以省略；但which没
有此用法，be动词不可省。 二 . as除了代替整个句子，也可以代替主句中一
个特定的词。as在它引导的定语从句（限制性
或非限制性）中可以充当主语，宾语和表
语；在这种用法中它经常和such, so, the same
等词搭配使用；且当先行词中有such, so,
the same等词修饰时，关系代词通常必须用as。1. They were satisfied with this decision，as was
agreed beforehand (事先)
( as在从句中作主语，其先行词是this decision)
2 I never heard such stories as he tells.
( as在定语从句中作宾语，先行词是such stories)
3. The place doesn't look the same as it was
before liberation.
( as在定语从句中作表语，先行词是same)
4. Have you bought the same book as I referred
to yesterday?
( as在定语从句中作宾语，先行词是book)
例: Have you bought the same book as I referred to yesterday? ( as在定语从句中作宾语，先行词是book) Have you brought the same book that I gave you yesterday? ( that在定语从句中作宾语，先行词是book。 体会：本句中所指的书是同一本，上句中 指的是同一类书，而并不就是那一本。)
注意:
先行词中有the same修饰时，定语从句也可用that引导，但意思上有区别，as表示与此同类； that表示就是那一个(同物)。
1). when指时间，只能跟在hour, moment, day, month, season, year等后面。(=at / in / on which) 1. This is the hour when the place is full of children. 2. Do you remember the time when she came to see you? 2). where指地点，只能跟在village, town, city, home, place等的后面。 (=at / in / on which) 1. This is the place where I grew up. 2. She has gone home where she will stay for a day.
三．关系副词及其用法：
※ 关系副词在其引导的定语从句中作状语。
●●注意： how虽然可以表方式，但是它不能引导定语从 句来修饰way,而要用that或以in which的形式 引导定语从句。 I don’t know the way that (in which) I can solve this problem. (正确) I don’t know the way how I can solve this problem. (错误)
3). why 指原因，通常跟在reason后面( 不强调
reason时可以省略)。 ( = for which)
1. Do you know the reason why he didn’t come?
2. That’s the reason (why) she doesn’t like it.
A.关系词在定语从句中既是引导词又在定语从句 中担任一定的句子成分。因此，如果关系词在 定语从句中作宾语，那么定语从句中就不能再 出现宾语了。 例：Some of the boys (that / who / whom) I invited didn’t come. (正确) Some of the boys (that / who / whom) I invited them didn’t come. (错误)
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