主语从句PPT课件.pptVIP

Step5PracticeNounClauses---ThesubjectclauseByDebbyGrammarWhatpartdoestheunderlinedpartserveasineachsentence?1Atreehasfallenacrosstheroad.2Youareastudent.3Tofindyourwaycanbeaproblem.4Smokingisbadforyou.5“Howdoyoudo?”isagreeting.Whatshesaidisnotyetknown.Thatweshallbelateiscertain.Itiscertainthatweshallbelate.03040201主语从句

（NounClausesastheSubject）定义：用作主语的从句叫主语从句，它是名词性从句之一。引导主语从句的连接词有：连词that,whether；连接代词who,what和which；连接副词when,where,how和why。主语从句的连接词连词that(无词义,不作成分,不能省略);whether(是否),if不能位于句首。Thathewillcomeandhelpusiscertain.Whetherwewillsucceedisstillaquestion.Itisnotknownifhewillcome.注意:已确定的事由that引导;没决定的事由whether引导.主语从句常用it作形式主语放句首因而我们常见到这种句式：It+be+n./adj/-ed从句（that,whether,etc.)例：Itsapitythatyoushouldhavetoleave.=Thatyoushouldhavetoleaveisapity.ItisgreatthatIhaveateacherlikeyou.=ThatIhaveateacherlikeyouisgreat.2)连接代词who，what，which,whatever,whichever,whoever充当成分，有具体意义Whatseemseasytosomepeopleseemsdifficulttoothers.Whichsidewillwinisnotclear.3)连接副词when，where，how，why等。Whyhediditremainsamystery.Whentheywillstartisnotknownyet.Howhebecameagreatscientistisknowntousall.2.位置：主语从句可以前置，也可以后置。用it做形式主语，而把主语从句，在句末，常用下面几种句型。1）It+be+表语+主语从句表语：（名词，形容词，过去分词）Itisafact(ashame,apity,goodnews…)that…Itisstilluncertainwhetherheiscomingornot.ItisanhonourthatIwasinvitedtoattendthemeeting.Itiscertainthatshewilldowellinherexam.ItistruethatItoldhereverything.ItissaidthatMr.GreenhasarrivedinBeijing.ItisreportedthatChinahassentanothermanmadeearthsatelliteintoorbit.2）It+不及物动词+主语从句2）It+不及物动词+主语从句Itseemed(happened,doesn’tmatter,hasturnedout)that…Ithappensthattheywereabsent.ItseemsthatAliceisnotcoming