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1主语从句讲解及练习主语从句一、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.主语从句主要有三类：（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.你想获得奖牌看起来是不可能的。Thatyouaresoindifferentbothersme.你如此冷淡使我很烦恼。Thatshesurvivedtheaccidentisamiracle.她在事故中幸免于难简直是奇迹。（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。例如：Whethersheiscomingornotdoesn’tmattertoomuch.她来不来都无关紧要。（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.你所需要的是更多的训练。2WhatIwanttoknowisthis.我想知道的就是这事。Whateverwedoistoservethepeople.我们无论做什么都是为人民服务。（4）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。)eg:Whereweshouldleaveitisaproblem.Whentheywillcomehasn’tbeenmadepubic.他们什么时候来还不知道。三.注意点:1.it做形式主语,而将主语从句放在句末（尤其是当谓语较短时）。例如：Thatlighttravelsinstraightlinesisknowntoall.光沿直线传播，这是众所周知的事。=Itisknowntoallthatlighttravelsinstraightlines.众所周知光沿直线传播。Whentheplaneistotakeoffhasnotbeenannounced.飞机何时起飞还没有宣布。=Ithasnotbeenannouncedwhentheplaneistotakeoff.还没有宣布飞机何时起飞。(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.他想要的是本书。例如：Hasitbeensettledwhowillbesenttocarryoutthetask?3谁将被派去执行这项任务决定了吗？固定用法和译法（1）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.这一切是怎么发生的是个谜。Itiscommonknowledgethatthewhaleisnotafish.鲸鱼不是鱼，这是常识。ItisnosurprisethatBobshouldhavewonthegame.鲍勃会赢得这场比赛，这不足为奇。（2）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.4例如：Itisobviousthatconductorsandinsulatorsarebothimportantinindustry.很明显导体和绝缘体在工业中都很重要。Itisdoubtfulwhethershewillbeabletocome.她是否能来令人怀疑。Itwasreallyastonishingthatherefusedtotalktoyou.他拒绝和你说话真是令人惊讶。Itisessentialthatheshouldbeherebytheweekend.周末之前，他应该到这里是必要的。Itseemsobviousthatwecannotgoonlikethis.很明显我们不能这样下去了。（3）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.大家都认为他是最好的选手。Itisestimatedthatthevaseis2000yearsold.据估计这个花瓶有2000年的历史。Itisusedtobethoughtthatanewstarmustbeduetoacollisionbetweentwostars.5过去一直认为新星是由于两颗星星之间碰撞产生的。Ithasnotbeenmadeclearwhenthenewroadistobeopenedtotraffic.还没弄清楚这条路将开始通车。ItdoesnotmatterifImissedmytrain,becausethereisanotherlater.没有赶上这趟火车没有关系，稍晚还有一趟。IthappenedthatIsawhimyesterday.碰巧我昨天看见他了。当“及物动词+宾语”较短时，也可用这种结构。例如：ItshockedmethatPeterdidnottellanybodywherehewas.让我吃惊的是彼得没有告诉任何人他在哪里。Itdoesnotinterestmewhetheryougoornot.我对你去不去不感兴趣。2.只用whether不用if引导主语从句.填空11._____asmuchasone-fifthofalltimberharvestedisnotused.2._____somemammalscametoliveintheseaisnotknown.3._____wehaveachievedisattributedtotheguidanceofourparents.4._____wealthydoesnotnecessarilymeanthatamanisgreedy.5.Although_____happenedinthisdevelopedcountrysoundslikesciencefiction,itcouldoccurelsewhereintheworld.6._____shehadforgottentotakehernotebook.7.Iamsurethat_____shesaidiswrong.68.Welostourwayintheforest,and_____mademattersworsewasthatitwasgettingdark.9._____somemammalscametoliveintheseaisnotknown.10._____ornotisstilluncertain.11.It’s_____he’llbeabletocome.12._____heisatworkintheheartofthebigcityorathomeinthequietsuburb,Dick’slifeistiedtomachines.13._____hesawbothsurprisedandfrightenedhim.14._____isaspellofwarmsunshine.15._____isapitythatheshouldfeelsoupset.16._____aspoonfulofsoilcantellussomuchaboutthestructureandearlyhistoryofthemoon.17._____younominatewillbeelected.18._____bookyouborrowmustbereturnedwithinaweek.19._____ofusgetshomefirststartscooking.20._____ordershegivesareobeyed.填空21.________makesmistakesmustcorrectthem.2.Itworriedherabit____herhairwasturninggrey.3.Whenandwhyhecamehere________yet.4.________isnoreasonfordismissingher.5.________Tomlikedtoeatwasdifferentfrom________.76.________wegoswimmingeveryday________usalotofgood.7.It________Bobdrivesbadly.8.It'suncertain________theexperimentisworthdoing.9.________theboydidn'ttakemedicinemadehismotherangry.10.____wecan'tgetseemsbetterthan____wehave.11.____youdon'tlikehimisnoneofmybusiness.12..____we'llgocampingtomorrowdependsontheweather.13._________isgoingtodothejobwillbedecidedbythePartycommittee.14._______we'llfinishtranslatingthebookdependsonthetime.15.______hewon'tgothereiscleartoallofus.16.______thehousewillbebuiltwillbediscussedattomorrow'smeeting.17.._______youcomeornotisuptoyou.18.._______makesmistakesmustcorrectthem.19.._______teamwillwinthematchisamatterofpublicconcern.20..________leavestheroomlastoughttoturnoffthelights.A.isnotknownC.ThefactthatshewasafewminuteslateD.What…whatyouhadexpected主语从句练习题[即学即用]I.用适当的词填空,使句子意思完整。1.______hedidn’tattendthemeetingyesterdaywasn’tquiteclear.2.TheForeignMinistersaid,“Itisourhope______t