语法:名词性从句名词性从句相当于名词,可分别作主句的主语、表语、宾语和同位语。因此,名词性从句成分为主语从句、表语从句、宾语从句和同位从句。(一)引导名词性从句的连接词1、连接代词:who,whose,whom,what,which。有词义,在从句中担任成分,如主语、表语、宾语、或定语等。2、连接副词:when,where,why,how。有词义,在从句中担任成分,作状语。3、连接词:that,whether,if,asif。that无词义,在从句中不担任成分,有时可省略;if(whether),asif虽有词义,但在从句中不担任成分。(二)主语从句1、主语从句在复合句作主语。e.g.Whowillgoisnotimportant.2、用it作形式主语,主语从句放在句末。e.g.Itdoesn’tmattersomuchwhetheryouwillcomeornot.3、that引导主语从句时,不能省略。e.g.Thathesuddenlyfellilllastweekmadeussurprised.注意:that从句作主语和宾语时,可以用it来替换成以下几种结构表达。(A)Itisclear/certain/likely/true/surprisingthat…(B)Itisapity/shame/goodidea/nowonderthat...(C)Itissaid/reported/believed/known/thought/suggestedthat…(D)Itseems/happensthat。如:IthappenedthatIwentoutlastnight.ItissaidthatChinawillwinintheWorldCup.(三)表语从句1、表语从句在复合句中作表语,位于系动词之后。e.g.Thequestionwaswhocouldgothere.(四)宾语从句1、宾语从句在复合句中作宾语。引导宾语从句的连词that一般可省略。e.g.Ihope(that)everythingisallright.2宾语从句中的连接词that有时可省有时又不可省,在以下几种情况中that不能省略:(A)当that从句和主句谓语动词之间有插入词语或者从句主语之间有插入语时,that不可省略;(B)当that从句与另一名词性从句并列作宾语时,that不能省;(C)当that作介词宾语时,that不可省掉。如:Hejudgedthat,becausehewasachild,hedidnotunderstandwineEveryoneknewwhathappenedandthatshewasworried.Thereasonliesinthatsheworksharderthantheothersdo.3、whether和if的用法。1)whether和if在宾语从句中可以互换,但是作介词宾语时连接词一般用whether。如:Italldependsonwhethertheywillcomeback.2)后面直接跟ornot时用whether。如:Ididn’tknowwhetherornothehadarrivedinWuhan.3)主语从句、表语从句、同位语从句中只能用whether。如:Whetherthemeetingwillbeputoffhasnotbeendecidedyet.Thequestioniswhethertheyhavesomuchmoney.Weoughttodiscusscarefullythequestionwhetherwecandoitornot.4)whether常与or连用表示一种选择,if不能这样用Thequestionofwhethertheyaremaleorfemaleisnotimportant.5)whether也可与动词不定式连用但if不能。如:Ihavenotdecidedwhethertogoornot.6)宾语从句提前时用whether不用if。如:Thankyou,butwhetherI’llbefreeI’mnotsureatthemoment.7)引导条件状语从句时,必须用if.Ifitrainstomorrow,wewon’tgototheSummerPalace.(五)同位语从句同位语从句在句中作某一名词的同位语,一般位于该名词(如:news、fact、suggestion、truth、plan、belief、doubt、possibility、idea、promise等)之后,说明该名词的具体内容。e.g.Ihavenoideawhenhewillbeback.Thefactthathehadnotsaidanythingsurprisedeverybody.注意:同位语从句与定语从句中that的区别。同位语从句中的连词that只起连接作用,在从句中不担当任何句子成分;而定语从句中的关系代词that在句中做宾语或主语,宾语与先行词有修饰关系。如果句子是同位语从句,就应用连词that而不能用which.同位语从句一般放在表具体含义的名词后解释名词的含义或内容,如以下名词:news、fact、suggestion、truth、plan、belief、doubt、possibility、idea、promise等,而定语从句只是对先行词的限定和修饰。如:TheyexpressedthehopethattheywouldcometovisitChinaagain.ThehopesheexpressedisthattheywouldcometovisitChinaagain.(六)疑问词+ever和nomatter+疑问词的区别。①疑问词+ever可引导名词性从句,在主从句中要充当一定的部分。如:Whoeverbreakstherulemustbepunished.Youcanchoosewhateveryoulikeintheshop.②疑问词+ever还可引导让步状语从句。如:Whoeverbreakstherule,hemustbepunished,Whateveryoudo,youmustdoitwell.③nomatter+疑问词只能引导让步状语从句。如:Nomatterwhatyoudo,youmustdoitwell.Nomatterwhobreakstherule,hemustbepunished.(七)名词性从句中主句和从句的时态一致(1)宾语从句中主句和从句的时态保持一致,但如果从句中表示提示的是客观现象,虽然主句是过去时态,从句仍用一般现在时。如:Hello,Ididn’tknowyouwereinLondon.Howlonghaveyoubeenhere?Theteachertoldusthatlighttravelsataveryhighspeed.(2)主语从句作主语相当于单数第三人称作主语,谓语动词用单数,如果由and连接两个或两个以上的主语从句作主语时,谓语动词用复数;由两个或多个连接词引导一个主语从句,谓语动词用单数。如:Whenthemeetingwillbegin______notbeendecidedyet.Whentheywillstartandwheretheygo_______notbeendecidedyet.Whenandwherethemeetingwillbegin_______notbeendecided.(八)、名词性从句的词序名词性从句在句中要用陈述句语序。如:Heaskedmewhatwasthematterwithme.We’veheardthenewsthatwe’llmoveintothenewhouse.Whateveryousaywillinterestusall.(九)that和what的区别。that引导名词性从句时,在主从句中不以当任何句子成分,也没有任何含义;而what引导名词性从句时,在主从句中都要充当一定主语、宾语、表语或定语,what的意思是:“什么,…的….”Whatsurprisedmemostishercheerfulexpressiononherface.★语法:名词性从句几大考点及热点名词性从句包括主语从句、宾语从句、表语从句和同位语从句。因为它是从句,因此具有句子的特点,有主、谓成分;同时又具有名词性特点,所以可以在句子中作主语、宾语、表语或同位语。一、引导词what与that的区别引导主、宾、表语从句时,what要充当主语、宾语或表语等句子成分,that不作任何成分,而只在语法上起连接作用。例如_________wecan’tgetseemsbetterthan_________wehave.A.What;whatB.What;thatC.That;thatD.That;what解析:本句包含一个主语从句和一个宾语从句,且两个从句都缺乏宾语,可见两个引导词都必须充当从句的宾语,所以答案为A项。在下面的例句中,that不充当任何成分,只起语法连接作用(因为句子本身不缺成分):ThattheformerIraqpresidentSaddamwascapturedhasbeenproved.二、引导词whether和if的区别通常,引导主语从句、表语从句和同位语从句时,连词要用whether,而不用if;习惯上也只能说whetherornot,而不说ifornot.例如:_________themeetingwillbeheldinBeijingisnotknownyet.A.WheneverB.IfC.WhetherD.That解析:题中的从句位于句首,不难知道这是一个主语从句,根据句意,答案为C项。但如果宾语或主语从句为否定句时,只能用that,不能用whether引导。如:Thatyoudon’tlikehimisnoneofmybusiness.三、名词性从句的语序与别的从句一样,名词性从句必须用自然语序,即使在疑问句中,从句也不倒装(而在主句上倒装)。例如:Noonecanbesure_________inamillionyears.A.whatmanwilllooklikeB.whatwillmanlooklikeC.manwilllooklikewhatD.whatlookwillmanlike解析:由于从句不能倒装,所以答案只能选A项。同时还须注意,从句的引导词必须始终置于句首。四、who/whoever,what/whatever等的区别一般说来,what/who等含特指意义,而whatever,whoever等含泛指意义。例如:Itisgenerallyconsideredunwisetogiveachild_________heorshewants.A.howeverB.whateverC.whicheverD.whenever解析:答案为B项。Whatever引导一个宾语从句,并且作wants的宾语。这里的whatever不能改成what,因为题意想表达的显然是“无论孩子要什么,就给他/她什么是不明智的”,具有泛指的概念。同时要注意,这里whatever也不能改用nomatterwhat,因为后者只能引导状语从句。五、where,when,why等连接副词引导的名词性从句where,when,why等连接副词也可以引导名词性从句,使用的关键是:这个词必须符合句子的逻辑要求。例如:—IdrovetoZhuhaifortheairshowlastweek.—Isthat_________youhadafewdaysoff?A.whyB.whenC.thatD.where解析:答案为A项,why引导的从句作表语,同时why在从句中作原因状语。又如:—Doyouremember_________hecame?—Yes.Ido,hecamebycar.A.howB.whenC.thatD.if解析:答案为A项。从答语hecamebycar可