主语从句以及练习题

主语从句以及练习题主语从句：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）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。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.ThathewillrefusethispieceofadviceisimpossibleItisimpossiblethathewillrefusethispieceofadvice.it为形式主语2.Thattheyshouldlikeeachotherisnatural.Itisnaturalthattheyshouldlikeeachother.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2)Itis+adj.+从句It’scertainthat…肯定…Itispossiblethat...很可能……Itisunlikelythat...不可能……Itisobviousthat…很明显…Itisnecessary\important\natural\...that…3)It+不及物动词+从句Ithappenedthat...碰巧……Itoccurredtomethat…我突然想起…4)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……2.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)Whoeverbreaksthelawwillbepunished3)连接副词when，where，how，why等。Whentheywillleaveisnotdecided.Wheresheisfromisunknown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.正：Whenhewillcomeisnotknown规律一、主语从句一律用陈述语序，即主语在前，谓语在后。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。例3.Ifthemeetingwillbeputoffhasnotbeendecidedyet正：Whetherthemeetingwillbeputoffhasnotbeendecidedyet.规律三、whether可以引导主语从句，放在句首，但if不能例4.Thatwhetherhewillhelpothersisafact.正：Thathewillhelpothersisafact.规律四、主语从句中的连词不能重叠使用。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。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.Exercises:1.Dhashelpedtosavethedrowninggirlisworthpraising.A.WhoB.TheoneC.AnyoneD.Whoever2.ItwasAhesaiddisappointedme.A.what;thatB.that;thatC.what;whatD.that;what3.Bwe’llgocampingtomorrowdependsontheweatherA.IfB.WhetherC.ThatD.Where4.Ahesaidatthemeetingsurprisedeverybodypresent.A.WhatB.ThatC.ThefactD.Thematter5.Bwastoreturntoschool.A.ThatreallyinterestedhimB.WhatreallyinterestedhimC.WhichreallyinterestedhimD.Thatinteresthimreally6、_A__hemadeanimportantspeechatthemeetingwastrue.A.ThatB.WhyC.WhatD.How7、_B__we’llgocampingtomorrowdependsontheweather.AIfBWhetherCThatDWhere8.__D_isknowntousallthatAmericaisadevelopedcountry.AWhic