主语从句详解.docx

主语从句详解.docx

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主语从句详解

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：

Thatyouwillwinthemedalseemsunlikely.

Thatyouaresoindifferentbothersme.

Thatshesurvivedtheaccidentisamiracle.

（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：

Whetherwewillholdapartyintheopenairtomorrowdependsontheweather.

Whethersheiscomingornotdoesn’tmattertoomuch.

（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：

Whatyouneedismorepractice.WhatIwanttoknowisthis.

Whateverwedoistoservethepeople.

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=anythingthat;whoever=anyonewho.要注意和whatever,whoever引导的让步状语从句的区别.

Whoeverbreaksthelawshouldbepunished.（主语从句）

（＝Anyonewhobreaksthelawshouldbepunished.）

Whoeverbreaksthelaw,heshouldbepunished.（让步状语从句）

（＝Nomatterwhobreaksthelaw,heshouldbepunished.）

（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:

Whereweshouldleaveitisaproblem.

Whentheywillcomehasn’tbeenmadepubic.

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：

Thatlighttravelsinstraightlinesisknowntoall.

=Itisknowntoallthatlighttravelsinstraightlines.

Whentheplaneistotakeoffhasnotbeenannounced.

=Ithasnotbeenannouncedwhentheplaneistotakeoff.

（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:

Itisabookwhathewants.

对:

Whathewantsisabook.

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：

ItwasreportedthattheUSwasundertheterroristattack.

Aswasreported,theUSwasundertheterroristattack.

（2）常见用it作形式主语的复合句结构

A.Itis+名词+从句

Itisafactthat…事实是……

Itisgoodnewsthat………是好消息

Itisaquestionthat………是个问题

Itiscommonknowledgethat………是常识

类似的名词还有：

apity；awonder；agoodthing；nowonder；surprise等.

例如：

Itisamysterytomehowitallhappened.

Itiscommonknowledgethatthewhaleisnotafish.

ItisnosurprisethatBobshouldhavewonthegame.

It’sapitythatyoumissedthefilm.

B.Itis+形容词+从句

Itisnecessarythat…有必要……

Itisclearthat…很清楚……

Itislikelythat…很可能……

Itisimportantthat…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：

Itisdoubtfulwhethershewillbeabletocome.

Itwasreallyastonishingthatherefusedtotalktoyou.

Itisessentialthatheshouldbeherebytheweekend.

Itseemsobviousthatwecannotgoonlikethis.

Itisnecessarythatyou（should）masterthecomputer.

ItisimportantthatastudentlearnEnglishwell.

Itislikelythatahurricanewillarrivesoon.

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.Itis+过去分词+从句

Itissaidthat…据说……

Itisreportedthat…据报道……

Ithasbeenprovedthat…已证明……

Itmustbeprovedthat…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;madeclear;foundout,etc.

例如：

Itisthoughtthatheisthebestplayer.

Itisestimatedthatthevaseis2000yearsold.

Itisusedtobethoughtthatanewstarmustbeduetoacollisionbetweentwostars.

Ithasnotbeenmadeclearwhenthenewroadistobeopenedtotraffic.

Itissaidthathewaskilledintheearthquake.

D.Itseems（happened/appears/doesn’tmatter/makesnodifference/occurred…）that…

Itseemsthattheywillwinthegame.

Itmakesnodifferencewhetherhewillattendthemeetingornot.

ItdoesnotmatterifImissedmytrain.

IthappenedthatIsawhimyesterday.

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 mammalscame 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 occurelsewhere 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.________makesmistakesmustcorrectthem.

A.WhatB.ThatC.WhoeverD.Whatever

2.Itworriedherabit____herhairwasturninggrey.

A.whileB.thatC.ifD.for

3.Whenandwhyhecamehere________yet.

A.isnotknownB.arenotknown

C.hasnotknownD.havenotknown

4.________isnoreasonfordismissingher.

A.Becauseshewasafewminuteslate

B.Owingtoafewminuteslate

C.Thefactthatshewasafewminuteslate

D.Beingafewminuteslate

5.________Tomlikedtoeatwasdifferentfrom________.

A.That…thatyouhadexpectedB.What…thatyouhadexpected

C.That…whatyouhadexpectedD.What…whatyouhadexpected

6.________wegoswimmingeveryday________usalotofgood.

A.If...doB.That...doC.If...doesD.That...does

7.It________Bobdrivesbadly.

A.thinksthatB.isthoughtwhatC.thoughtthatD.isthoughtthat

8.It'suncertain________theexperimentisworthdoing.

A.ifB.thatC.whetherD.how

9.________theboydidn'ttakemedicinemadehismotherangry.

A.ThatB.WhatC.HowD.Which

10.____wecan'tgetseemsbetterthan____wehave.

A.What,whatB.What,thatC.That,thatD.That,what

11.____youdon'tlikehimisnoneofmybusiness.

A.WhatB.WhoC.ThatD.Whether

12..____we'llgocampingtomorrowdependsontheweather.

A.IfB.WhetherC.ThatD.Where

13._________isgoingtodothejobwillbedecidedbythePartycommittee.

A.ThatB.WhyC.HowD.Who

14._______we'llfinishtranslatingthebookdependsonthetime.

A.WhenB.WhyC.WhatD.That

15.______hewon'tgothereiscleartoallofus.

A.HowB.WhatC.WhyD.This

16.______thehousewillbebuiltwillbediscussedattomorrow'smeeting.

A.IfB.WhereC.ThatD.What

17._______youcomeornotisuptoyou.

A.WhatB.IfC.WhyD.Whether

18._______makesmistakesmustcorrectthem.

A.WhoB.AnyoneC.WhoeverD.Anybody

19._______teamwillwinthematchisamatterofpublicconcern.

A.WhichB.ThatC.IfD.How

20.Whoisthisfactory__________someforeignfriendsvisitedlastFriday?

A.thatB.whereC.whichD.theone

21.Isthisfactoryyouvisitedtheotherday?

A.thatB.whereC.inwhichD.theone

22.________leavestheroomlastoughttoturnoffthelights.

A.AnyoneB.ThepersonC.WhoeverD.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、asthough（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.

Thetroubleisthatweareshortofmoney.困难是我们资金短缺.

ThatiswhystonewallsareusedinsteadoffencesaroundNewEnglandfields.这就是为什么在新英格兰用石头墙而不用栅栏的原因.

Atthattime,itseemedasifIcouldn'tthinkoftherightwordanyhow.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.

Thetroubleis（that）shehaslosthismoney.麻烦的事是他丢了钱.

Thequestioniswhetherweneedmoreicecream.问题是我们是否还需要一些冰淇淋.

Theproblemwasthatitwastoovaluableforeverydayuse.问题是它作为日常之用太贵重了.

Whatshecouldn’tunderstandwasthatfewerandfewerstudentsshowedinterestinherlessons.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,