主语从句详解.doc

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/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 matter 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, 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. 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, whoever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, 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“（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 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 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 life 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
3.When 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
7.It ________ Bob drives badly.
A. thinks that B. is thought what C. thought that D. is thought that
8.It'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
21.Is 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 D.Who

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、whether、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.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抽象名词, 如question(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 lessons. 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 seems 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（being,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
　　［答案］ D
　　［解析］ 下划线处之后是包含一个原因状语从句的表语从句, 如果看不出它是充当整个句子结构的表语从句将难以把握整个句子的意思.因此, 应选择可引导名词性从句且不充当任何成分的that.
　　［考题2］ You are saying that everyone should be equal, and this is ____ I disagree.
　　A. why B. where C. what D. how
　　［答案］ B
　　［解析］ 下划线处的引导词引导系动词is后的表语从句并在该表语从句中充当地点状语(“disagree”属于不及物动词, “I disagree”本身是完整的主谓结构), 下划线应填入引导词where, 表语从句“where I disagree”的意思是“我不同意之处、 我不同意的地方”.
　　［考题3］ — I drove to Zhuhai for the air show last week.
　　— Is that ____ you had a few days off?
　　A. why B. when C. what D. where
　　［答案］ A
　　［解析］ 下划线处的引导词引导与系动词is连用的表语从句并在该表语从句中充当原因状语, 下划线应填入表示“因此……”(指因某种原因所造成的结果)的引导词why.
　　［考题4］ ____ she couldn’t understand was ____ fewer and fewer students showed interest in her lessons.
　　A. What; why B. That; what C. What; because D. Why; that
　　［答案］ A
　　［解析］ 第一个下划线处的引导词引导主语从句并在该主语从句中充当宾语, 特指她所不理解的事情, 应填入关系代词型的引导词what； 第二个下划线处表示“因此……”(指因某种原因所造成的后果, 由why引导对应的名词性从句)而不是“为什么……”(指原因、 理由, 由because引导对应的名词性从句), 应填入引导词why.
　　［考题5］ ____ made the school proud was ____ more than 90% of the students had been admitted to key universities.
　　A. What; because B. What; that
　　C. That; what D. That; because
　　［答案］ B
　　［解析］ 第一个下划线处的引导词引导主语从句并在该主语从句中充当主语, 特指令校方骄傲的事情, 应选用关系代词型的引导词what； 第二个下划线处引导表语从句表示原因、 理由, 应由that引导对应的名词性从句.
　　［考题6］ — Are you still thinking about yesterday’s game?
　　— Oh, that’s ____.
　　A. what makes me feel excited B. whatever I feel excited about
　　C. how I feel about it D. when I feel excited
　　［答案］ A
　　［解析］ A选项的意思是“令我感觉激动的事物”； B选项的意思是“我觉得激动的任何事物”； C选项的意思是“我对它感觉的方式”； D选项的意思是“令我感觉激动的时间”.四个选项中A最适合跟代表“game”的主语that对应, 充当表语从句.
　　表语从句与宾语从句的关系
　　不属于的
　　宾语从句和表语从句都属于名词性从句.其作用跟名词在句中的作用相同.故充当宾语的句子叫宾语从句, 充当表语的句子叫表语从句.
　　宾语从句
　　(1)对于宾语从句要掌握以下三点
　　①语序: 从句的语序必须是陈述句语序, 即“主语 + 谓语”这种形式.
　　②时态: 当主句是一般现在时或一般将来时的时候, 从句可以是任何时态, 而当主句是一般过去时的时候, 从句, 从句时态必须是过去时范围的时态, 即(一般过去时, 过去进行时, 过去完成时, 过去将来时).
　　③连接词: 当从句意思完整, 主句意思肯定时, 连接词用that, 且可以省去, 当从句意思完整, 主句意思不确定或含否定含意时, 常用if或whether(是否), 当从句意思不完整时, 连接词则是代替不完整部分的特殊疑问词.
　　表语从句
　　在句子中起表语作用的从句叫做表语从句, 位于主句系动词的后面.表语从句的引导词和主语从句的引导词相同.也是名词性从句的一种.
　　如： What the police want to know is when you enred red the room警察想知道的是你什么时候进的房间.
　　The The trouble is that we are short of funds困难是我们缺乏资金.
　　This This is what we should do这是我们应当做的.
　　That”s s why I want you to work there那就是我要你在那儿工作的原因.
　　His His first question was whether Mr. Smith had arrived yet他的第一个问题是史密斯先生到了没有.
　　注意：从句中的疑问句用正常语序, 即陈述语序.
　　as as if, as though, becau也可用来引导表语从句.
　　She She seems as if she had done a great thing她看起来好像做了一件大事.
　　It It is because you eat too much那是因为你吃得太多了.

表从练习
一
1. The question is ________ we will have our sports meet next week.
A. that B. if C. when D. whether
2．The reason why he failed is ________he was too careless.
A. because B. that C. for D. because of
3. Go and get your coat. It’ s ________you left it
A. where B. there C. there where D. where there
4．The problem is _________to take the place of Ted
A. who can we get B. what we can get
C. who we can get D. that we can get
5. What I want to know is ______ he likes the gift given by us.
A. that B. if C. whether D.不填
6. The reason is_____I missed the bus.
A. that B. when C. why D. what
7. That is __ ___ we were late last time.
A. that B. when C. why D. what
8. She looked _________ she were ten years younger.
　A. that  B. like C. as    D. as though
9.—I fell sick!