名词性从句Nounclauses名词性从句是由if,whether,that和各种疑问词充当连接词所引导的从句,其作用同名词一样。包括主语从句,宾语从句,表语从句和同位语从句。一.主语从句主语从句是在复合句中充当主语的从句,通常放在主句谓语动词之前或由形式主语it代替,而本身放在句子末尾。1.It作形式主语和it引导强调句的比较It作形式主语代替主语从句,主要是为了平衡句子结构,主语从句的连接词没有变化。而it引导的强调句则是对句子某一部分进行强调,无论强调的是什么成分,都可用连词that。被强调部分指人时也可用who。例如:Itisapitythatyoudidn’tgotoseethefilm.Itdoesn’tinterestmewhetheryousucceedornot.Itisinthemorningthatthemurdertookplace.(=Inthemorningthemurdertookplace.)ItisJohnthatbrokethewindow.(=Johnbrokethewindow.)2.用it作形式主语的结构(1)Itis+名词+从句Itisafactthat…事实是…Itisanhonorthat…非常荣幸Itiscommonknowledgethat是常识(2)Itis+形容词+从句Itisnaturalthat…很自然…Itisstrangethat…奇怪的是…(3)It+不及物动词+从句Itseemsthat…似乎…Ithappenedthat…碰巧…(4)It+is/was+过去分词+从句Itisreportedthat…据报道…Ithasbeenprovedthat…已证实…Itissaid/thought/hoped/told/believed+that….3.主语从句不可位于句首的五种情况(1)Itissaid,(reported)…结构中的主语从句不可提前。例如:ItissaidthatPresidentBushwillvisitourcountrynextweek.(right)ThatPresidentJiangwillvisitourschoolnextweekissaid.(wrong)(2)Ithappensthat..,Itoccursthat…结构中的“that”从句不可提前。例如:Itoccurredtohimthathefailedintheexamination.(right)Thathefailedintheexaminationoccurredtohim.(wrong)(3)Itdoesn’tmatterhow/whether…结构中的主语从句不可提前。例如:Itdoesn’tmatterwhetherheiswrongornot.(right)Whetherheiswrongornotdoesn’tmatter.(wrong)(4)含主语从句的复合句是疑问句时,主语从句不可提前。例如:Isitlikelythatitwillrainintheevening?(right)Isthatwillrainintheeveninglikely?(wrong)4.what与that在引导名词性从句时的区别what引导名词性从句时在从句中1)充当句子成分(主、宾、表);2)本身有词义。而that1)只起连接作用;2)本身没有词义;3)不在从句中担任成分。Forexample:1)Whatyousaidyesterdayisright.(=Allthatyou.2)Thatsheisstillaliveisapuzzle.你昨天说的话是对的。她仍活着是一个谜。二.宾语从句宾语从句就是在复合句中作宾语的名词性从句,通常放在主句谓语动词(及物动词)或介词之后。1.作动词的宾语(1)由that引导的宾语从句(that通常可以省略),例如:Ihearthathejoinedthearmy.(2)由what,whether(if)引导的宾语从句,例如:1)Shedidnotknowwhathadhappened.2)Iwonderwhetheryoucanchangethisnoteforme.(3)动词+间接宾语+宾语从句。例如:Shetoldmethatshewouldacceptmyinvitation.2.作介词的宾语例如:Oursuccessdependsonhowwellwecancooperatewithoneanother.3.作形容词的宾语例如:Iamafraid(that)I’vemadeamistake.that引导的从句常跟在下列形容词后作宾语:anxious,sure,confident,determined,glad,proud,surprised,worried,sorry,thankful,ashamed,disappointed,pleased,satisfied,content等。4.It可以作为形式宾语It不仅可以作为形式主语,还可以作为形式宾语而真正的宾语that从句则放在句尾,特别是在带复合宾语的句子中。例如:Wemustmakeitcleartothepublicthatwearedoinganimportantjob.7.否定的转移若主句谓语动词为think,consider,suppose,believe,expect,guess,imagine等,其后的宾语从句若含有否定意义,一般要把否定词转移到主句谓语上,从句谓语用肯定式。例如:Idon’tthinkthisdressfitsyouwell.(我认为这件衣服不适合你穿。)三.表语从句表语从句在复合句中作表语的名词性从句,放在系动词之后,一般结构是“主语+连系动词+表语从句”。可以接表语从句的连系动词有be,look,remain,seem等.另外,常用的还有thereasonisthat…和Itisbecause等结构。例如:1)Thequestioniswhetherwecanmakegoodpreparationinsuchashorttime.2)Thisiswhywecan’tgetthesupportofthepeople3)Butthefactremainsthatwearebehindtheotherclasses.4)Thereasonwhyheislateforschoolisthathemissedtheearlybus.四.同位语从句同位语从句就是在复合句中作名词的同位语的名词性从句。1.同位语从句的功能同位语从句对于名词进一步解释,说明名词的具体内容,一般由that引导,例如:1)Theking’sdecisionthattheprisonerwouldbesetfreesurprisedallthepeople.2)Theorderthatallthesoldiersshouldstaystillisgivenbythegeneral.2.同位语在句子中的位置同位语从句有时可以不紧跟在它所说明的名词后面,而是被别的词隔开。例如:HegotthenewsfromMarythatthesportsmeetingwasputoff.3.同位语从句与定语从句的区别(1)定语从句中的that既代替先行词,同时以在从句中作某个成分(主语或宾语),而同位语从句中的that是连词,只起连接主句与从句的作用,不充当句中任何成分。(2)定语从句是形容词性的,其功能是修饰先行词,对先行词加以限定,描述定的性质或特征;同位语从句是名词性的,其功能是对名词进行补充说明。例如:1)ThenewsthathetoldmeisthatTomwouldgoabroadnextyear.(他告诉我的消息是汤姆明年将出国。)(第一个that引导的从句是定语从句,that在从句中作宾语)2)ThenewsthatTomwouldgoabroadistoldbyhim.(汤姆将出国的消息是他讲的。)(同位语从句,that在句中不作任何成分)