名词性从句讲解.doc

名词性从句名词性从句主语从句、宾语从句、表语从句、同位语从句名词性从句是由if,whether,that和各种疑问词充当连接词所引导的从句，其功能同名词一样。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。例如：Itisapitythatyoudidntgotoseethefilm.Itdoesntinterestmewhetheryousucceedornot. 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)itis不及物动词从句Itseemsthat似乎Ithappenedthat碰巧(4)it过去分词从句Itisreportedthat据报道Ithasbeenprovedthat已证实3. 由连词that 或者whether引导的主语从句：这种情况下 that 和whether只是引导作用 不担当成分，不能省略，并且可以转变成it形式主语。That the earth is round is true。it is true that the earth is round。 Whether he will come or not hasnt been decided. 4. 由连接代词或者连接副词引导的主语从句：连接代词who,which和连接副词when，where，how，why都可以引导主语从句，可以分别担任主语，宾语和状语，不能省略，可以改为it引导的主语从句。Who let out the news remained unknown-it remained unknown who let out the news.Why he didnt come here is not clear to anyone.-it is not clear to anyone why he didnt come.5. 以关系代词what, whatever whoever whichever等引导的主语从句：whoever leaves the office should tell me。（这里whoever做主语）改成定语从句：Any one who leaves the office should tell me。Whenever the Olympic Games will be held in Beijing is not known yet.6.What与that在引导主语从句时的区别What引导主语从句时在句时在从句中充当句子成分，如主语、宾语、表语，而that则不然。例如：1)Whatyousaidyesterdayisright.2)Thatsheisstillaliveisaconsolation.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：Iheardthathejoinedthearmy.(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: Oursuccessdependsuponhowwellwecancooperatewithoneanother.3.作形容词的宾语例如：Iamafraid(that)Ivemadeamistake.That引导的从句常跟在下列形容词后作宾语：anxious,aware,certain,confident,convinced,determined,glad,proud,surprised,worried,sorry,thankful,ashamed,disappointed,annoyed,pleased,hurt,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(也可能是to do) 从句则放在句尾，特别是在带复合宾语的句子中。例如：Wehearditthatshewouldgetmarriednextmonth.He found it pretty hard to learn both English and French well at the same time. 5.后边不能直接跟that从句的动词这类动词有allow,refuse,let,like,cause,force,admire,condemn,celebrate,dislike,love,help,take,forgive等。这类词后可以用不定式或动名词作宾语，但不可以用that引导的宾语从句。例如：Iadmiretheirwinningthematch.(right)Iadmirethattheywonthematch.(wrong)6.否定的转移若主句谓语动词为think,consider,suppose,believe,expect,fancy,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：Idontthinkthisdressfitsyouwell.（我认为这件衣服不适合你穿。）7.注意事项：1. 宾语从句时态要与主语保持相应的一致和变化。2. 从句的语态要变为陈述语序。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。引导表语从句的that一般不可省略。另外，常用的还有thereasonisthat和Itisbecause等结构。例如：1)Thequestioniswhetherwecanmakegoodpreparationinsuchashorttime.2)Thisiswhywecantgetthesupportofthepeople.3)Butthefactremainsthatwearebehindtheotherclasses.4)Thereasonheislateforschoolisthathemissedtheearlybus.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)Thekingsdecisionthattheprisonerwouldbesetfreesurprisedallthepeople.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. 一般用于同位语从句的抽象名词有：news， idea，belief, doubt, fact, rumor, order, hope, answer3.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，同时可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）whether 与if 在名词性从句中：1引导宾语从句时，whether和if可以互换，但是出现or not时候只能用whether I dont know whether/ if I can come. I dont know whether I can come or not.2. 如果宾语从句是否定结构，则用if。 I dont care if he doesnt show up.4. 介词宾语从句只能用whether 引导。 We worried about whether he was in god health