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名词性从句一．定义：在句子中起名词作用的句子叫名词性从句(NounClauses）。名词性从句的功能相当于名词词组,它在复合句中能担任主语、宾语、表语、同位语、介词宾语等，因此根据它在句中不同的语法功能，名词性从句又可分别称为主语从句、宾语从句、表语从句和同位语从句。1.Hiswordsaretrue.Whathesaidistrue.2.Thedogsensedsomethingdelicious.Thedogsensedthattherewassomethingdeliciousnearby.3.Thesearehiswords.Thesearewhathesaid.4.MyChineseteacher,MrWang,isakindperson.Thenewsthattheplanehadcrashedmadeussad.二．引导名词性从句的连接词连词：在从句中不充当成分，只起连接作用that,无实义whether,if是否asif\asthough似乎，好像连接代词：有词义，在句中担任主语，表语，定语或宾语。what,什么who,谁whom,谁，作宾语whose,谁的which,哪一个whatever,whoever……也可以引导。连接副词：有词义，在句中担任状语。when,什么时候where,什么地方why,为什么how,怎么样howmany,howmuch,howoften三．主语从句1.作句子主语的从句叫主语从句。Whetherhewillcomeornotisnotknown.他来不来还不清楚。Whathewantstotellusisnotclear.他要跟我们说什么，还不清楚。Whowillwinthematchisstillunknown.谁能赢得这场比赛还不得而知。Itisknowntoushowhebecameawriter.我们都知道他是如何成为一名作家的。WheretheEnglisheveningwillbeheldhasnotyetbeenannounced.英语晚会将在哪里举行，还没有宣布。Thatheislateforschoolmakestheteacherveryangry.他上学迟到让老师很生气。2.有时为避免句子头重脚轻，常用形式主语it代替主语从句作形式主语放于句首，而把主语从句置于句末。主语从句后的谓语动词一般用单数形式。常用句型如下：（1）It+be+名词+that从句Eg.Itisapitythatwewon'tbeabletogotothesouthtospendoursummervacation.Itisstillamysterywhatcausedtheaccident.（2）It+be+形容词+that从句Eg.Itiscertainthathewillwinthematch.Itistruethathehasmadeaveryimportantdiscoveryinchemistry.Itisverylikelythattheywillholdameeting.Itisstrangethatheshoulddothat.Itisimportantthatweallshouldattendthemeeting.Itisstrangethatthemanshouldhavestucktohissillyideas.（3）It+be+动词的过去分词+that从句Eg.Itissaidthathehasgonetoshanghai.(=Heissaidtohavegonetoshanghai)ItisknowntoallthatthegunpowderwasfirstinventedbytheChinese.Itissuggestedthatthework（should）bedonewithgreatcare.（4）It+不及物动词+that从句Eg.Itseemsthathehasseenthefilm.(=Heseemstohaveseenthefilm)Ithappenedthatthetwocheatswerethere.(=Thetwocheatshappenedtobethere)ItoccurredtomethatIhadforgottentolockmydoor.ItsuddenlyhitmethatIhadforgottentolockmydoor.ItstruckmethatIhadforgottentolockmydoor.Itturnedoutthatnobodyrememberedtheaddress.注意：在主语从句中用来表示惊奇、不相信、惋惜、理应如此等语气时，谓语动词要用虚拟语气“(should)+do”，常用的句型有：Itisnecessary(important,natural,strange,etc.)that…Itissuggested(requested,proposed,desired,etc.)that…3.主语从句的时态：不受主句的时态影响和限制。（1）Thathefinishedwritingthecompositioninsuchashorttimesurprisedusall.（2）Whetherwewillgoforanoutingtomorrowremainsunknown.（3）Whowillbeourmonitorhasn'tbeendecidedyet.（4）Whomwemuststudyforisaquestionofgreatimportance.（5）Whatcausedtheaccidentremainsunknown.（6）Whateveryoudidisright.（7）Whothewatchbelongstowaslostisunknown.4.that与what引导主语从句的区别what有词义，在句中担任主语，表语，定语或宾语。that无词义，不作任何成分，只起连接作用Eg.Whathasmadehimmadisnotknownyet.Thatsheisstillaliveisaconsolation.四．宾语从句1.定义：名词句用作宾语的从句叫宾语从句。2.由连接词that引导宾语从句时，that在句中不担任任何成分，在口语或非正式的文体中常被省去，但如从句是并列句时,第二个分句前的that不可省。例如：HehastoldmethathewillgotoShanghaitomorrow.他已经告诉我他明天要去上海。Wemustneverthink(that)wearegoodineverythingwhileothersaregoodinnothing.我们决不能认为自己什么都好，别人什么都不好。Weallthink(that)sheisworkinghardandthatshewillsurelygotoaverygooduniversity.我们都认为她学习非常努力，一定能进一个非常好的大学。3.在demand、order、suggest、decide、insist,desire,request,command等表示要求、命令、建议、决定等意义的动词后，宾语从句常用“（should）+动词原形”。例如：Iinsistthatshe(should)doherworkalone.我坚持要她自己工作。Thecommanderorderedthattroops(should)setoffatonce.司令员命令部队马上出发。4.可运用形式宾语it代替的宾语从句①动词find,feel,consider,make,believe等后面有宾语补足语的时候,则需要用it做形式宾语而将that宾语从句后置.Ithinkitnecessarythatwetakeplentyofhotwatereveryday.我认为每天多喝开水是有必要的.IfeelitapitythatIhaven’tbeentotheget-together.我没去聚会,感觉非常遗憾.IhavemadeitarulethatIkeepdiaries.我每天写日记成了习惯.Weallfinditimportantthatwe(should)makeaquickdecisionaboutthismater.我们都认为对这件事马上做出决定很重要.②有些动词带宾语从句时需要在宾语与从句前加it这类动词主要有:hate,take,owe,have,seeto.Eg.Ihateitwhentheytalkwiththeirmouthsfulloffood.我讨厌他们满嘴食物时说话.Hewillhaveitthatourplanisreallypractical.他会认为我们的计划确实可行.Wetakeitthatyouwillagreewithus.我们认为你会同意我们的.Hetookitforgrantedthathisgirlfriendwouldcomebackagain.他想当然的认为女朋友会再回来。Whenyoustarttheengine,youmustseetoitthatcarisinneutral.开启发动机时,一定要使汽车的离合器处于空挡位置.③若宾语从句是wh-类,则不可用it代替Weallconsiderwhatyousaidtobeunbelievable.我们都认为你所说的是不可信的.Wediscoveredwhatwehadlearnedtobevaluable.我们发现我们所学到的东西都是有用的.5.用who，whom,which,whose,what,when,where,why,how,whoever,whatever,whichever等关联词引导的宾语从句相当于特殊疑问句，应注意句子语序要用陈述语序。例如：Iwanttoknowwhathehastoldyou.我想知道他告诉了你什么。Shealwaysthinksofhowshecanworkwell.她总是在想怎样能把工作做好。Shewillgivewhoeverneedshelpawarmsupport.凡需要帮助的人，她都会给予热情的支持。6.用whether或if引导的宾语从句，其主语和谓语的顺序也不能颠倒，仍保持陈述句语序。此外，whether与if在作“是否”的意思讲时在下列情况下一般只能用whether，不用if：a.引导主语从句并在句首时；b.引导表语从句时；c.引导从句作介词宾语时；d.从句后有“ornot”时；e.后接动词不定式时。Eg.Whetherthereislifeonthemoonisaninterestingquestion.月球上有没有生命是个有趣的问题。Thequestioniswhethersheshouldhavealowopinionofthetest?现在的问题是她是否应该有一个低意见的测试？Everythingdependsonwhetherwehaveenoughmoney.一切要看我们是否有足够的钱。Iwonderwhetherhewillcomeornot.我想知道他来还是不来。Canyoutellmewhethertogoortostay?你能否告诉我是去还是留？7.注意宾语从句中的时态呼应，当主句动词是现在时，从句根据自身的句子情况，而使用不同时态。例如：HestudiesEnglisheveryday.（从句用一般现在时）HestudiedEnglishlastterm.（从句用一般过去时）Iknow(that)hewillstudyEnglishnextyear.（从句用一般将来时）HehasstudiedEnglishsince1998.（从句用现在完成时）当主句动词是过去时态（could,would除外），从句则要用相应的过去时态，如一般过去时，过去进行时，过去将来时等；当从句表示的是客观真理，科学原理，自然现象，则从句仍用现在时态。例如：HesayshestudiesEngl