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GrammarGrammar主语从句：做主语用的名词性从句，因其在复合句中做主语，又称主语从句，引导主语从句的有连词that，whether，连接代词who，what，which，连接副词when，where，how，why等。1）从属连词：that，whether等.that引导主语从句只起引导作用，本身无实际意义，在主语从句中不充当任何成分，但不能省略。Thathewillwiniscertain.他肯定会赢。Whetherhe’llcomehereisn’tclear.他是否会来这里还不清楚。注意:由that引导的主语从句有时为了使句子结构平衡,避免“头重脚轻”,常用it作形式主语,而把从句放在后面。例如:1.Thathewillrefusethispieceofadviceisimpossible.______________________________________________________________________________2.Thattheyshouldlikeeachotherisnatural._____________________________________*it为形式主语Itisnaturalthattheyshouldlikeeachother.Itisimpossiblethathewillrefusethispieceofadvice.这样就构成了下面一些常用句型:1)Itis+n.+从句Itisapity/shamethat...遗憾的是……Itisasurprisethat…令人惊奇的是…Itisafactthat……是事实Itiscommonknowledgethat……是常识*_______________(很遗憾)welostthematch.*______________(这是事实)hecheatedintheexam.ItisapitythatItisafactthat2)Itis+adj.+从句It’scertainthat…肯定…Itispossiblethat...很可能……Itisunlikelythat...不可能……Itisobviousthat…很明显…Itisnecessary\important\natural\...that…*_________________(很可能)shewillcomebacktomorrow.*_________________(很明显)thismeasureiseffective.+(should)+do…ItispossiblethatItisobviousthat3)It+不及物动词+从句Ithappenedthat...碰巧……Itoccurredtomethat…我突然想起…*________________(刚好)Icameintotheofficeatthattime.*____________________(我突然想起)Iforgettosenttheletter.IthappenedthatItoccurredtomethat4)It+be+过去分词+从句Itissaidthat...据说……Itisknowntoallthat...众所周知……Itisreportedthat...据报道……Itisbelievedthat...据信……;人们相信……Itissuggestedthat+(should）do...建议……Itmustbeadmittedthat…必须承认……Itcannotbedeniedthat…不可否认……Itmustbepointedoutthat…需指出的是……*___________________(据报道)20peoplewerekilledintheaccident.*______________________(建议)weshouldeatmorevegetableanddomoreexercise.ItisreportedthatItissuggestedthat2.连接代词who，what，which,whatever,whichever,whoever(Who,whom,which,what可以和ever构成合成词，和what一样引导从句，ever起到强调作用。此类主语从句不能用形式主语it引导，它们在句子中担任成分，不能省略，语序为陈述语序)Whatmanyscientistsbelieveisthattheearthisround…Whowilltakepartinthemeetinghasnotbeendecided.Whoeverbreaksthelawwillbepunished.Whichstudentwillwinisuncertain.Whateverwassaidheremustbekeptsecret.这里说的话都应当保密。Whoevermakesmistakesmustcorrectthem.凡犯了错误的人都必须改正。3)连接副词when，where，how，why等。Whytheysuddenlydisappearedstillremainsamystery.Whentheywillleaveisnotdecided.Wheresheisfromisunknown.Howwewillpaintthehousehasnotbeendecided.注意:1）主语从句在句首时，必须由连接词引导，不能省略这些连接词；但是如果用it做形式主语，而把主语从句放在句末时，从属连词that可以省略。误：Theyshouldlikeeachotherisnatural.正：Thattheyshouldlikeeachotherisnatural.正：Itisnatural(that)theyshouldlikeeachother.2)如果主语从句放在句首，不能用if引导，但是如果用it做形式主语，而把主语从句放在句末时，也可以用if引导.或把if改为whether误：IfMaryreallyheardhimisreallydoubtful.正：ItwasdoubtfulifMaryreallyheardhim.正:WhetherMaryreallyheardhimisreallydoubtful.Completethesentencesusingwhat,whether,where,when，who,why,howorthat.1.(_____isneededforsuccess)isyourhardwork.3.(_____wewillgotomorrow)hasn’tbeendecidedyet.2.(______theywillarrive)hasbeentoldtotheteacher.4.(______canjoininthesportmeet)isdecidedbytheteacher.5.(________itwillrainornot)isnotclear.WhatWhen/HowWhere/whetherWhoWhether主语从句作主语时，谓语动词一般用单数形式。Conclusion:主语从句的规律：找出下列句子中的错误，并总结规律例1.Whenwillhecomeisnotknown.规律一、主语从句一律用陈述语序，即主语在前，谓语在后。正：Whenhewillcomeisnotknown.主语从句的规律：例2.Hewillnotcometothemeetingthiseveningistrue.正：Thathewillnotcometothemeetingthiseveningistrue.规律二、连词that在从句中无实际意义，但不能省略。主语从句的规律：例3.Ifthemeetingwillbeputoffhasnotbeendecidedyet.正：Whetherthemeetingwillbeputoffhasnotbeendecidedyet.规律三、whether可以引导主语从句，放在句首，但if不能主语从句的规律：例4.Thatwhetherhewillhelpothersisafact.正：Thathewillhelpothersisafact.规律四、主语从句中的连词不能重叠使用。主语从句的规律：例5.Whenhewillcomeareapuzzle.正：Whenhewillcomeisapuzzle.规律五、含主语从句的主句谓语动词多用单数第三人称形式。主语从句的规律：1.Whatheneedsisthatbook.2.Whatheneedsaresomebooks.规律六、what引导的主语从句，可根据表语决定主句动词的单复数形式。规律七、主语从句为了避免头重脚轻现象，用it做形式主语，而把从句放在后面。Thattheearthturnsaroundthesunisknowntoall.Itisknowntoallthattheearthturnsaroundthesun.找出错误，并给出理由：1.Whereshallwespendtheholidayisn’tdecided.2.Youhavemadeamistakeisafact.3.Ifthepolicemanwillcomeisnotcertain.4.Thatiscertainthatwecanwin.weshallWhetherItThatyouhave5.Itisorderedweshouldleaveatonce.6.Wherehecomesfromareamystery.7.Whatwhetherhelikesthejobisnotclear.8.Whoheisandwhereheisfromisimportant.9.Whathesawisthestarsinthesky.thatisxareareExercises:PartOne:主语从句单选题1.hashelpedtosavethedrowninggirlisworthpraising.A.WhoB.TheoneC.AnyoneD.WhoeverD2.Itwashesaiddisappointedme.A.what;thatB.that;thatC.what;whatD.that;whatA3.we’llgocampingtomorrowdependsontheweather.A.IfB.WhetherC.ThatD.WhereB4.hesaidatthemeetingsurprisedeverybodypresent.A.WhatB.ThatC.ThefactD.ThematterA5.wastoreturntoschool.A.ThatreallyinterestedhimB.WhatreallyinterestedhimC.WhichreallyinterestedhimD.ThatinteresthimreallyB6.makesmistakesmustcorrectthem.A.WhatB.ThatC.WhoeverD.WhateverC7.yourmenhavebeenonmylandwithoutpermission.A.ItseemsthatB.ThereseemstobeC.ThatseemsD.ItseemsforA8.Ithasalwayspuzzledmetheoldmanliedaredsilkribbonontheyoungtree.A.thatB.whyC.whereD.whatB1.___hemadeanimportantspeechatthemeetingwastrue.A.ThatB.WhyC.WhatD.How2.___we’llgocampingtomorrowdependsontheweather.AIfBWhetherCThatDWhere3.Itworriedherabit___herhairwasturningg