主语从句讲解及其练习

1、_主语从句一、主语从句的连词分三类（ 1 ）从属连词引导的主语从句（ that whether if）that 引导的主语从句:引导词 that 无含义 / 在句中不做成分/不可以省。 That引导主语从句通常用 it 作形式主语。例如： That you will win the medal seems unlikely.That she survived the accident is a miracle.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 不能在开头，只能用whether 。Whether we wi

2、ll hold a party in the open air tomorrow depends on the weather.Whether she is coming or not doesntmatter too much.（2 ） 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, whatever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.Whatever we do is to serve

3、 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, whoever引导的让步状语从句的区别。精品资料_如： Whoever breaks the law should be punished.（主语从句）（ Anyone who breaks the law should be punished.）Whoever breaks the law, h

4、e should be punished.（让步状语从句）（ No matter who breaks the law, he should be punished.）（3 ）用连接副词when, where, why, how 引导的名词性从句 (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 hasntbeen made pubic.三、 it 作形式主语的主语从句有时为了考虑句子平衡， 通常在主语从句处使用形式主语it，而将真正的主语从句移至句末。这分四种情况：(1) 对于以连

5、词 that 引导的主语从句，通常用形式主语it 替代主语从句：<a> It is + 名词 +从句It is a fact that 事实是； It is good newsthat 是好消息； It isaquestionthat 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。It is a mystery to me how it all happened.It is common knowledge that the

6、whale is not a fish.It is no surprise that Bob should have won the game.<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 重要的是精品资料_类似的形容词还有：strange;natural;obvious;true;good;wonderful;possible;unlikely;quite; unusual; certain; evide

7、nt; worth-while; surprising; interesting; astonishing, etc.It is doubtful whether she will be able to come.It is essential that he should be here by the weekend.It seems obvious that we can not go on like this.It is necessary that you（should ） master the computer.需要注意的是这类主语从句中，谓语动词很多为“（ should ）动词原形

8、”，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 proved 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 used to be tho

9、ught 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.<d> It seems不及物动词（ happened / appears / doesnttmatter / makes no difference /occurred） that 主语从句不可提前It makes no difference whether he will attend the meetin

10、g or not.It does not matter if I missed my train.It happened that I saw him yesterday.(2) 对于以连接代词 (副词 )引导的主语从句， 可以使用形式主语代主语从句， 也可直接在句首使用主语从句：精品资料_Whether they would support us was a problem.他们是否会支持我们还是一个问题。It was a problem whether they would support us.他们是否会支持我们还是一个问题。(3) 对关系代词型 what 引导的主语从句，通常直接将主语

11、从句放在句首。如：What we need is money.我们需要的是钱。What I want to know is this.我想知道的就是这一点。有时也可将助用形式主语。如：It is clear enough what he meant.他是什么意思很清楚。(4) 如果句子是疑问句，则必须用带形式主语it 的结构：Is it true that he is the girlsfather?他是那女孩的父亲，是真的吗？How is it that you are late again?你怎么又迟到了？四、连词that 的省略问题引导主语从句的连词that 有时可省，有时不能省，其原则

12、是：若that 引导的主语从句直接位于句首，则that 不能省略；若that 引导的主语从句位于句末，而在句首使用了形式主语it，则 that 可以省略：That you didn tgo to the talk was a pity.很遗憾你没去听报告。(that 不可省 )It was a pity (that) you didntgo to the talk.很遗憾你没去听报告。(that 可省 )高考题：1 、 It neveroccurredto me_C_youcouldsucceedin persuadinghim to changehismind.( 陕西高考 )A which

13、B whatC thatD If首先要理解句意.这句话的意思是说,我从来没想到你能够成功地说服他去改变,而不是我从来没想到你能否精品资料_成功地说服他改变.第二 ,It never occurred to me是用于对于某个已发生的事实表示惊讶、吃惊的句型,所以这里 you could succeed in persuading him to change这个事实只能用that 来引导； if 是用于引导一个不确定性（uncertainty ）的 ,这里不可以用.2、 It's obvious to the students_B_they should get well prepare

14、d for their future.(天津卷 )A asB thatC whichD Whether考查名词性从句中的主语从句用法.此处要分析句子结构, 看出 it 为形式主语 ,代替 that theyshould get well prepared for their future,并且本句意思完整,故选 D.3 、 _B_somepeopleregardasadrawbackisseenasaplugbymanyothers.(2010 ·北京)A WhetherB WhatC ThatD How考查名词性从句中的主语从句用法.此处要分析句子结构, 看出 it 为形式主语 ,

15、代替 that theyshould get well prepared for their future,并且本句意思完整,故选 D.4、 It is uncertain_A_side effect the medicine will bring about， although about twothousand patients have taken it.(2010·浙江)A thatB howC whatDWhetherwhether是“是否”的意思这里应该是选B,what.精品资料_因为跟后面side effect连起来 ,what side effect,一起表示“是什么

16、副作用”整句话的意思是“虽然有两千多个病人服用的这个药,但是对于其带来的具体的什么副作用还是不明确的 . ”根据意思来选择,只能是 Bthat,how,whether都不能表达这个意思.主语从句练习题1._C_ makes mistakes must correct them.A. What B. That C. Whoever D. Whatever这句话强调的是普遍性，所以用whoever 任何人，而不是特指谁2. It worried her a bit _B_ her hair was turning grey.A. while B. that C. if D. for解析：句意：她的

17、头发渐渐变得花白,使她不安 .该题常错选C、 D. 用 if 和 whether 引导该句则句意不通 .主语从句较长时,多放在句子后部,用 it 作形式主语 ,此时 ,that 也不能省略 .3.When and why he came here _A_ yet.A. is not known B. are not knownC. has not known D. have not known因为 ,首先 ,这是现在完成时,yet 是现在完成时的提示词, 但是也可以是一般现在时第二 ,When and why he came here这个整个句子做主语,凡是句子做主语的,都是单数 ,因此精品资

18、料_是 IS第三 ,这是被动 ,他何时来为什么来,还尚未为人所知悉如果是现在完成时,是 has not been known4. _C_ is no reason for dismissing her.A. Because she was a few minutes lateB. Owing to a few minutes lateC. The fact that she was a few minutes lateD. Being a few minutes late首先 ,句子不完整 ,缺的是可以充当主语的名词性的从句.A和 B排除,都不是D 如果真的要选的话,应该为： Being a

19、few minutes late is no reason for her beingdismissed. 这个叫主语一致吧C 由 the fact 引导的同位语名词性从句符合要求,主干是：the fact is no reason for dismissingher.5. _D_ Tom liked to eat was different from _.A. That that you had expected B. What that you had expectedC. That what you had expectedD. What what you had expected选wh

20、at 作 expected 的宾语that 不能做句子成分意思是“汤姆喜欢吃的东西 ,与他以前期盼的东西不一样.6._D_ we go swimming every day _ us a lot of good.A. If.do B. That.doC. If.does D. That.does精品资料_That 指后面每天去游泳的事因为是单 3 形式所用用does其实去掉中间的we go swimming every day（用来补充that ）简单来看 ,整句就是That doseus a lot of good加上 we go swimming every day用来混淆视听罢了7.It

21、 _D_ Bob drives badly.A. thinks that B. is thought what C. thought that D. is thought that这种结构都用被动比如 it's said that最常见 ,只是中间换个词8.It's uncertain _C_ the experiment is worth doing.A. if B. that C. whether D. How应该用 whether, 对于不确定的事物要用whether, 不用 that. 肯定的时候采用that, 比较：I am sure of that he will

22、come.I am not sure whether he will come.9._A_ the boy didn't take medicine made his mother angry.A. That B. What C. How D. WhichWhat要充当成分 ,而它后面的句子完整了,主谓宾齐全 ,所以 what 改为 that相当于 what made his mother angry is that the boy didn't take medicine10._A_ we can't get seems better than _ we have.A

23、. What, what B. What, that C. That, that D. That, what主要测试主语从句和表语从句。第一空测试主语从句：句子 _ we can t get 中动词 get精品资料_需要宾语；第二空测试表语从句：句子_ we have中的动词have 也需要宾语，结合所给答案可知均选择what 最佳。11._C_ you don't like him is none of my business.A. What B. Who C. That D. Whether用 that, 句意是你不喜欢他 ,这不关我事 .That you don't li

24、ke him is none of my business .句中 is 是谓语 ,整个句子是主语从句.从句中you don't like him表达完整 ,内容结构都不缺,而主语从句不可省略引导词,于是我们用毫无意义的 that 来引导该从句.whether在从句中 ,有“是否”的意思,此时便不合要求.要用 whether, 则句子改成：Whether you like him or not is none of my business.你是否喜欢他 ,这不关我事 .12._B_ we'll go camping tomorrow depends on the weather

25、.A. If B. Whether C. That D. WhereB、 C、 D 三项均可引导主语从句,但是本句含有疑问的意思,因此 that 排除；根据句意,是否camping 和天气关系更为密切,所以 where 排除； if 虽也可表示“是否”,但其不能引导主语从句,也排除 .13._D_is going to do the job will be decided by the Party committee.A. That B. Why C. How D. Who这是个主语从句.Who is going to do the job为主语（从句） ,will be decided为谓语

26、 ,后面为状语 .主语从句一般不用how 引导 ,经常用 what that which who why引导 14._A_we'llfinish translating the book depends on the time.A. When B. Why C. What D. That我们何时翻译完这本书取决于时间.精品资料_when 引导的主语从句,从句主语 ,谓语完整 , 选择连系副词 ,根据意思选择.15._C_he won't go there is clear to all of us.A. How B. What C. Why D. This为什么他没有来到这里我们所有人都清楚16._B_the house will be built will be discussed at tomorrow's