主语从句讲解及其练习

第8页主语从句一、主语从句的连词分三类〔1〕附属连词引导的主语从句〔thatwhetherif〕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：Thatyouwillwinthemedalseemsunlikely.Thatshesurvivedtheaccidentisamiracle.

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。Whetherwewillholdapartyintheopenairtomorrowdependsontheweather.Whethersheiscomingornotdoesn’tmattertoomuch.

〔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：Whatyouneedismorepractice.

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。如：Whoeverbreaksthelawshouldbepunished.〔主语从句〕〔＝Anyonewhobreaksthelawshouldbepunished.〕Whoeverbreaksthelaw,heshouldbepunished.〔让步状语从句〕〔＝Nomatterwhobreaksthelaw,heshouldbepunished.〕〔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:Whereweshouldleaveitisaproblem.Whentheywillcomehasn’tbeenmadepubic.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)对于以连词that引导的主语从句，通常用形式主语it替代主语从句：<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。Itisamysterytomehowitallhappened.Itiscommonknowledgethatthewhaleisnotafish.ItisnosurprisethatBobshouldhavewonthegame.<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.Itisdoubtfulwhethershewillbeabletocome.

Itisessentialthatheshouldbeherebytheweekend.

Itseemsobviousthatwecannotgoonlikethis.Itisnecessarythatyou〔should〕masterthecomputer.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：Ithasnotbeenmadeclearwhenthenewroadistobeopenedtotraffic.

<d>Itseems不及物动词〔happened/appears/doesn’t’tmatter/makesnodifference/occurred…〕that…主语从句不可提前Itmakesnodifferencewhetherhewillattendthemeetingornot.ItdoesnotmatterifImissedmytrain.

IthappenedthatIsawhimyesterday.(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：Whethertheywouldsupportuswasaproblem.他们是否会支持我们还是一个问题。Itwasaproblemwhethertheywouldsupportus.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，通常直接将主语从句放在句首。如：Whatweneedismoney.我们需要的是钱。WhatIwanttoknowisthis.我想知道的就是这一点。有时也可将助用形式主语。如：Itisclearenoughwhathemeant.他是什么意思很清楚。(4)如果句子是疑问句，那么必须用带形式主语it的构造：Isittruethatheisthegirl’sfather?他是那女孩的父亲，是真的吗？Howisitthatyouarelateagain?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，其原那么是：假设that引导的主语从句直接位于句首，那么that不能省略；假设that引导的主语从句位于句末，而在句首使用了形式主语it，那么that可以省略：Thatyoudidn’tgotothetalkwasapity.很遗憾你没去听报告。(that不可省)Itwasapity(that)youdidn’tgotothetalk.很遗憾你没去听报告。(that可省)高考题：1、Itneveroccurredtome___youcouldsucceedinpersuadinghimtochangehismind.(陕西高考)A．which B．whatC．that D．if2、It'sobvioustothestudents________theyshouldgetwellpreparedfortheirfuture.(天津卷)A．asB．thatC．whichD．whether3、________somepeopleregardasadrawbackisseenasaplugbymanyothers.(2021·北京)A．WhetherB．WhatC．ThatD．How4、Itisuncertain________sideeffectthemedicinewillbringabout，althoughabouttwothousandpatientshavetakenit.(2021·浙江)A．that B．howC．what D．whether主语从句练习题1.________makesmistakesmustcorrectthem.A.WhatB.ThatC.WhoeverD.Whatever2.Itworriedherabit____herhairwasturninggrey.A.whileB.thatC.ifD.for3.Whenandwhyhecamehere________yet.A.isnotknownB.arenotknownC.hasnotknownD.havenotknown4.________isnoreasonfordismissingher.A.BecauseshewasafewminuteslateB.OwingtoafewminuteslateC.ThefactthatshewasafewminuteslateD.Beingafewminuteslate5.________Tomlikedtoeatwasdifferentfrom________.A.That…thatyouhadexpectedB.What…thatyouhadexpectedC.That…whatyouhadexpectedD.What…whatyouhadexpected6.________wegoswimmingeveryday________usalotofgood.A.If...doB.That...doC.If...doesD.That...does7.It________Bobdrivesbadly.A.thinksthatB.isthoughtwhatC.thoughtthatD.isthoughtthat8.It'suncertain________theexperimentisworthdoing.A.ifB.thatC.whetherD.how9.________theboydidn'ttakemedicinemadehismotherangry.A.ThatB.WhatC.HowD.Which10.____wecan'tgetseemsbetterthan____wehave.A.What,whatB.What,thatC.That,thatD.That,what11.____youdon'tlikehimisnoneofmybusiness.A.WhatB.WhoC.ThatD.Whether12..____we'llgocampingtomorrowdependsontheweather.A.IfB.WhetherC.ThatD.Where13._________isgoingtodothejobwillbedecidedbythePartycommittee.A.ThatB.WhyC.HowD.Who14._______we'llfinishtranslatingthebookdependsonthetime.A.When