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主语从句详解
一、概述
在句子中起名词作用的各种
从句统称为名词性从句
.
根据它们在句中的语法作用
,
这类从句
又可分为主语从句、同位语从句、表
语从句和宾语从句
.
二、主语从句主要有四类
（
1
）
由连词
that
引导的主语从句
:
引导词
that
无含义
/
在句中不做成分
/
< br>不可以省
.
例如：
That
you will win the medal seems unlikely.
That you are so indifferent bothers me.
That she survived the accident is a
miracle.
（
2
）
用连词
whether
引导的主语从句
:
whether
有含义
(
是否
)/
在句中不做成分
/
不可以省
.
注意：引导主语从句
,
不能用
if,
只能用
whether.
例如：
Whether we will hold a
party in the open air tomorrow depends on the
weather.
Whether she is
coming or not doesn’t matt
er too much.
（
3
）
用连接代词引导的主语从句
在由连接代词
who, whose, whom,
which, what, whoever, whomever, whichever, whateve
r
引导
的名词性从句中
,
其连接代词在句中起名词性作用
,
担当一定成分
.
例如：
What you need is more
practice. What I want to know is this.
Whatever we do is to serve the people.
注：
whatever /
whoever
的功用
whatever, whoever
在主语从句中不含疑问意
义
.
它引导主语从句
,
并在从句中作主语、宾语、
表语等
.
whatever = anything that; whoever =
anyone who.
要注意和
whatever, who
ever
引导的让步状语
从句的区别
.
Whoever breaks the law should be
punished.
（主语从句）
（＝
Anyone who breaks the law
should be punished.
）
Whoever breaks the law, he should be
punished.
（让步状语从句）
（＝
No matter who breaks the
law, he should be punished.
）
（
4
）
用连接副词
when, where,
why, how
引导名词性从句
(
其
连接副词有含义
,
在句中作状语
.)
例如
:Where we should leave it
is a problem.
When they will come
hasn’t been made pubic.
三、注意点
:
it
构成的主语从句
（
1
）由连词
that
引导的
主语从句
,
在多数情况下放到句子的后面
,
而用
代词
it
作形式主语
.
例如：
That light travels in
straight lines is known to all.
=It is
known to all that light travels in straight lines.
When the plane is to take off has not
been announced .
= It has not been
announced when the plane is to take off.
(
但当
what
引导的主语从句表
示
“…
的东西
”
时
,
一般不用
it
作形式主语
.)
错
:It is a book what he
wants.
对
:What he wants is a
book.
另外
,
需要注意的是
,
it
作形式主语代替主语从句时
, <
/p>
要注意和
as
引导的定语从句的区别
.
试
比较：
It was reported that the US was under
the terrorist attack.
As
was reported, the US was under the terrorist
attack.
（
2
）常见用
it
作形式主语的复合句结构
A. It is
+
名词
+
从句
It is a fact that…
事实是
……
It is good news that …
……
是好消息
It is a
question that … ……
是个问题
It is common knowledge that …
……
是常识
类似的名词还有：
a
pity
；
a
wonder
；
a good
thing
；
no
wonder
；
surprise
等
.
例如：
It is a mystery to me how
it all happened.
It is common knowledge
that the whale is not a fish.
It is no
surprise that Bob should have won the game.
It’s a pity that you missed the film.
B. It is +
形容词
+
从句
It is
necessary that …
有必要
……
It is clear that
…
很清楚
……
It is likely that …
很可能
……
It is important that …
重要的是
……
类似的形容词还有：
Strange; natural;
obvious; true; good; wonderful; possible;
unlikely; quite;
unusual;
certain; evident; worth-while; surprising;
interesting; astonishing, etc.
例如：
It is doubtful whether
she will be able to come.
It was really
astonishing that he refused to talk to you.
It is essential that he should be here
by the weekend.
It seems obvious that
we cannot go on like this.
It is
necessary that you
（
should
）
master the computer.
It is important that a
student learn English well.
It is likely that a hurricane will
arrive soon.
需要注意的是
,
这类主语从句中
,
谓语动词很多为<
/p>
“
（
should
）
＋动词原形
”
,
即要用虚拟语气
.
C. It is
+
过去分词
+
从句
It is said that …
据说
……
It is reported that …
据报道
……
It has been proved that …
已证明
……
It must be pro
ved that…
必须指出
……
类似的过去分词还有：
known; estimated;
expected; believed; thought; hoped; noted;
discussed;
required;
decided; suggested; demanded; made
clear; found out,etc.
例如：
It
is thought that he is the best player.
It is estimated that the vase is 2000
years old.
It is used to be thought
that a new star must be due to a collision between
two stars.
It has not been
made clear when the new road is to be opened to
traffic.
It is said that he was killed
in the earthquake.
D. It
seems
（
happened / appears /
doesn’t
matter / makes no
difference / occurred …
）
that
…
It seems that they will
win the game.
It makes no
difference whether he will attend the meeting or
not.
It does not matter if
I missed my train.
It happened that I
saw him yesterday.
主从练习
1. _____ as
much as one-fifth of all timber harvested is not
used.
A. The estimate
B. The
estimated
C. They are estimated
D. It is estimated that
2.
_____ some mammals came to live in the sea is not
known.
A. Which B. Since
C. Although D. How
3. _____ we
have achieved is attributed to the guidance of our
parents.
A. Whoever B. Whatever
C. However D. That
4. _____
wealthy does not necessarily mean that a man is
greedy.
A. For the reason that he is
B. Just because he is
C. The reason
of being D. That he is
5.
Although ___ happened in this developed country
sounds like science fiction,
it could occur
elsewhere in
the world.
A. which B. what
C. how D. it
6. _____ she had
forgotten to take her notebook.
A.
That occurred to her B. She occurred
that
C. To her that occurred
D. It occurred to her that
7. I am sure
that _____ she said is wrong.
A.
which B. all C. this D.
what
8. We lost our way in the forest,
and ____ made matters worse was that it was
getting dark.
A. that B.
which C. it D. What
9. _____ or not is still uncertain.
A.
He’s
coming
B. If he is coming
C. That coming D.
Whether
he’s
coming
10.
It’s
_____
he’ll
be able to come.
A. doubt whether B. doubtful C.
doubt it D. doubtful whether
11. ______ he is at work in the heart
of the big city or at home in the quiet
suburb,
Dick’s
l
ife is
tied to machines.
A. Whether B.
Till C. If D. Unless
12. _____ he saw both surprised and
frightened him.
A. That B.
When C. What D. Which
13. _____ is
warm sunshine.
A. What do we all need. B.
What all we need
C. What we need
D. What we all need
14.
_____ is a pity that he should feel so upset.
A. What B. That
C. He D. It
15. _____ a
spoonful of soil can tell us so much about the
structure and early history of the moon.
A. Remarkable B.
Quite remarkably
C. It is
remarkable that D. It is remarkable
fact that
16. _____ you nominate will
be elected.
A. Who B. Whom
C. Whomever D.
That’s
17. _____ book you borrow must be
returned within a week.
A. What
B. Which C. Whichever D.
That’s
18. _____
of us gets home first starts cooking.
A. Who B. Which C. Whichever
D. Anyone
1.________ makes mistakes must correct
them.
A. What B. That C. Whoever D.
Whatever
2. It worried her a bit ____
her hair was turning grey.
A. while B.
that C. if D. for
and why
he came here ________ yet.
A. is not
known B. are not known
C.
has not known D. have not known
4.
________ is no reason for dismissing her.
A. Because she was a few minutes late
B. Owing to a few minutes
late
C. The fact that she was a few
minutes late
D. Being a few
minutes late
5. ________ Tom liked to
eat was different from ________.
A.
That…that you had expected B. What …that you had
expected
C. That…what you
had expected D. What…what you had
expected
6.________ we go
swimming every day ________ us a lot of good.
A. If...do B. That...do C. If...does D.
That...does
________ Bob drives badly.
A. thinks that B. is thought what C.
thought that D. is thought that
's
uncertain ________ the experiment is worth doing.
A. if B. that C. whether D. how
9.________ the boy didn't take medicine
made his mother angry.
A. That B. What
C. How D. Which
10.____ we can't get
seems better than ____ we have.
A.
What, what B. What, that C. That, that D. That,
what
11.____ you don't like him is none
of my business.
A. What B.
Who C. That D. Whether
12..____ we'll
go camping tomorrow depends on the weather.
A. If B. Whether C. That D. Where
13._________is going to do the job will
be decided by the Party committee.
A.
That B. Why C. How D. Who
14._______we'll finish translating the
book depends on the time.
A. When B.
Why C. What D. That
15.______he won't
go there is clear to all of us.
A. How
B. What C. Why D. This
16.______the
house will be built will be discussed at
tomorrow's meeting.
A. If B. Where C.
That D. What
17._______you come or not
is up to you.
A. What B. If C. Why D.
Whether
18._______makes mistakes must
correct them.
A. Who B. Anyone C.
Whoever D. Anybody
19._______team will
win the match is a matter of public concern.
A. Which B. That C. If D. How
20. Who is this factory __________ some
foreign friends visited last Friday?
A.
that B. where C. which D. the one
this
factory
you
visited the other day?
A. that B. where
C. in which D. the one
22.________leaves the room last ought
to turn off the lights.
A. Anyone B.
The person C. Whoever
表语从句
1
、概述
用作表语的从句叫作表语从句
,
它位
于主句中的连系动词之后
.
引导表语从句的词有从属连
词
that
、
whet
her
、
as
though(if)
；关系代词
who, what,
which, whom, whose, whatever, whoever,
whomever,
whichever
等；关系副词
when, where,
why, how, however, whenever, wherever
等<
/p>
.
可以接表语从句的连系动词由
be,
look, remain, seem
等
.That
引导表语从句时
,
在口语中
,
间
或可以省略
.
The trouble is that we are short of
money.
困难是我们资金短缺
.
That is why stone walls are used
instead of fences around New England fields.
这就是为什么在新
英格兰用石头墙而不用栅栏的原因
.
At that time, it seemed as if I
couldn't think of the right word anyhow.
当时
,
我似乎怎么也想不出
一个恰当
的字眼来
.
2
、由从属连词
that,
whether
引导的表语从句
.
that
在引导表语从句时无词义
,
而
whether
有词义
,
意为、
“
是否
”
.
这时主句的主语常常是些
< br>抽象名词
,
如
questio
n(
问题
),
trouble(
麻烦
),
problem(
问题
),
result(
结果
),
chance(
可能性
),
suggestion(
建议
),
idea(
想法
), reason(
理由
)
等
.
表
语从句对主句主语进行说明、解释
,
使主语的
内容具体化
.
The trouble is (that) she
has lost his money.
麻烦的事是他丢了钱
.
The
question is whether we need more ice
cream.
问题是我们是否还需要一些冰淇淋
.
The problem was that it was too
valuable for everyday
use.
问题是它作为日常之用太贵重了
.
What she couldn’t understand was that
fewer and fewer students showed interest in her
l
essons.
我们不能理解越来越少的学生对他的课不感兴趣
.
3
、由关系代词引导的表语从句
.
关系代词
who, what, which, whom,
whose, whatever, whoever, whomever,
whichever
等引导表
语从句
,
在句中作主语、宾语、表语
,
关系代词不能省略
.
The
question is which of us should
go.
问题是我们哪一个应该去
.
The problem was who could do the
work.
问题是谁能做这项工作
.
That's what he is worrying
about.
那就是他在担心的事
.
That's what we should
do.
那是我们应该做的
.
4
、由关系副词引导的表语从句
.
Go and get your coat. It's where you
left it.
去把雨衣拿来
.
就
在你原来放的地方
.
I had neither a
raincoat nor an umbrella. That’s why I got wet
through.
我们既没伞也没雨衣
,
这
是我们淋湿的原因
.
That is how mice ruin many stores of
grain every
year.
那就是老鼠是怎样每年损害大量粮食的
.
That is what he is worried
about.
那就是他所担心的
.
5
、由连词
because, as
if/as though
等引导的表语从句
.
It looked as if it was going to
snow.
看起来好像要下雪了
.
That's because we never thought of
it.
这是因为我们从未想过此事
.
It see
ms as if he didn’t
know the answer.
好像他不知道答案
.
可以接表语从句的系动词有：
1
：
be
（
bein
g,been,am,is,are,was,were)
2: feel ,
seem , look, appear ,sound,
taste , smell
3:
stand , lie , remain ,keep, stay
4:
become ,get , grow , turn ,go ,come, run,
fall
5: prove, turn out
系动词的固定搭配
:
come true, fall asleep, fall ill, go
bad, come right, run wild
连接词：
that / whether /as if
/as
though
(if
不引导表语从句
)
连接代词：
who / whom / whose /
which
/ what
连接副词：
when /
where / why / how /
because
注：引导表语从句
的连词
that
间或可以省略
.
The truth is
（
that
）
I
didn't go there.
事实是我没去那儿
.
［考题
1
］
The traditional view is ____ we sleep
because our brain is “programmed” to
make us do so.
A. when B. why C. whether D. that
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