主语从句和主语从句的it.ppt

TheSubjectClause,Grammar,Makesentences,Itscertainthatwewillbelate.,Thatwellbelateiscertain.,Wedontknowwhetherheiscomingornot,Whetherheiscomingisnotknown.,Wedontknowwhathewantstotellus.,Whathewantstotellusisnotknown.,Whenyouwillcomebackdoesntmatter.,Itdoesntmatterwhenyouwillcomeback.,主语从句（NounClausesastheSubject）,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。,连接词：,that引导主语从句只起引导作用，本身无实际意义，在主语从句中不充当任何成分，但不能省略。,Thatshelefthimcuthimtotheheart.Thathewillcomeiscertain.,1）从属连词：that，whether等.,由whether及其他连词引导的主语从句放在句首，句后都可。,Whetheritwillpleasethemisnoteasytosay.,2)连接代词who，what，which,whatever,whichever,whoever,Whatseemseasytosomepeopleseemsdifficulttoothers.Whichsidewillwinisnotclear.,3)连接副词when，where，how，why等。,Whyhediditremainsamystery.Whentheywillstartisnotknownyet.Howhebecameagreatscientistisknowntousall.,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）,位置,ItissaidthatMr.GreenhasarrivedinBeijing.ItisreportedthatChinahassentanothermanmadeearthsatelliteintoorbit.,2.It+不及物动词+主语从句Itseemed(happened,doesntmatter,hasturnedout)that,Ithappensthattheywereabsent.ItseemsthatAliceisnotcomingtothepartyatall.,Itdoesntmatterwhethershewillcomeornot.,3.It+及物动词（被动语态）+主语从句,IthasbeendecidedthattheexhibitionwillnotopenonSundays.,注意:,1）主语从句在句首时，必须由连接词引导，不能省略这些连接词；但是如果用it做形式主语，而把主语从句放在句末时，从属连词that可以省略。,误：Theyshouldlikeeachotherisnatural.正：Thattheyshouldlikeeachotherisnatural.正：Itisnaturalthattheyshouldlikeeachother.,2)如果主语从句放在句首，不能用if引导，但是如果用it做形式主语，而把主语从句放在句末时，也可以用if引导.,误：IfMaryreallyheardhimisreallydoubtful.正：ItwasdoubtfulifMaryreallyheardhim.,4.用于Itisimportant/natural/necessary/impossiblethat.句型中,主语从句应使用虚拟语气,谓语动词用“should+动词原形”的形式,should有时可以省略。,5.在It+be+suggested/advised/ordered/requested/insisted/required中,that从句的谓语也应该用“should+动词原形”的形式,should有时可以省略。,(1)主语从句中用陈述语序WhatsheisafraidofistheirtakinghertoParis.(WhatissheafraidofWrong)(2)主语从句后谓语动词用第三人称单数Thattheyhaventphonedisstrange.(3)that引导的主语从句中，that不可被省略Thatpricewillgoupiscertain.,主语从句需注意的问题,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。被强调部分指人是也可用who/whom。例如：Itisapitythatyoudidntgotoseethefilm.Itdoesntinterestmewhetheryousucceedornot.Itisinthemorningthatthemurdertookplace.ItisJohnthatbrokethewindow.,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.,What在此引导主语从句,又做said的宾语,That只起连接作用,不做成分,what与that在引导主语从句时的区别,Describeyourmotherwithyourpartner.,Suggestedstructures