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Unit5WorkingtheLandLearningAboutLanguage主语从句【情境探究】观察上面对话:(1)句①中黑体部分在整个句子中作主语,句子作主语,称为_____从句。(2)句②是__作形式主语,that从句作真正主语。(3)句③中黑体部分作_____,称为主语从句。主语it主语【要义详析】一、主语从句是名词性从句的一种,在复合句中作主语,相当于名词。主语从句的位置可以在句首,也可以用it作形式主语,主语从句放在后面。二、主语从句的引导词1.连词that、whether,在主语从句中不充当任何成分,只起连接作用,不可省略,其中that没有词义,whether表示“是否”含义,但是不能换成if(如果)。2.连接代词what、who、which,在主语从句中充当主语、宾语、表语,不可省略。3.连接副词when、where、how、why,在主语从句中作状语,分别表示时间、地点、方式、原因等,不可省略。另外,wh-+ever,如whoever、however、whatever、whichever等也可引导主语从句。在句中充当主语、宾语、表语等,不可省略。【即学活用】语法填空(1)(2017·全国卷Ⅰ)_____I’mhopingtoaccomplishisthatmygenerationandyoungerstarttoreconsiderandunderstandthatjazzisnotblackandwhiteanymore.(2)________hewillattendthemeetingornotdoesn’tmatter.他是否参加会议并不重要。WhatWhether(3)______________________________________wasawonder.他在那次严重的交通事故中幸存下来是个奇迹。(4)____________________wasachallengingquestionatthetime.如何做到这一点在当时是一个具有挑战性的问题。ThathesurvivedtheserioustrafficaccidentHowthiscouldbedone(5)__________________________oughttoturnoffthelights.无论谁最后离开房间都应该关灯。Whoeverleavestheroomlast三、it作形式主语的主语从句在主语从句中如果主语太长,宾语或表语又太短,为了避免头重脚轻,保持句子平衡,通常会采用it作形式主语,真正的主语从句放在后面。常见的使用it作形式主语的结构:Itissaid/reported/believed/wellknownthat...Itisapitythat...Itisprobablethat...Ithappenedthat...Itisnowonderthat......【即学活用】(1)_______________Imetmyteacheronmywayhome.我在回家路上碰巧遇上我的老师。(2)_________________myfellowguestshadhadonlyafewbitesofeachdish.怪不得跟我在一起吃饭的客人,每道菜也就浅尝几口。IthappenedthatItisnowonderthat四、主语从句的语序时态问题主语从句和其他名词性从句一样必须使用陈述语序,尤其是当主语从句是疑问词引导的时候,主语从句的语序仍须使用陈述语序。Who/WhomhewillgotoBeijingwithremainsunknown.他将和谁一起去北京还不知道。主语从句的时态根据具体语境来确定,尤其是当when引导主语从句的时候,有些同学会和when时间状语从句混淆而误用现在时表将来。Whenhewillcomebackisstillunclear.他什么时候回来还不清楚。【即学活用】语法填空(1)_____isimpressiveisthatmycolleaguesmessagedus,worryingwhyKunandIdidn’tcomebackwiththeclockpointingto1am,2amoreven3am.What(2)______worriesmanypeopleisthatthesechemicalsmayevencausecancer.(3)_________breaksthelawshouldbepunished.WhatWhoever五、主语从句作主语相当于名词,和非谓语动词的动词-ing形式或者不定式作主语一样看作单数,句子谓语应该使用单数形式。Thatyoudon’tlikehimisnoneofmybusiness.你不喜欢他不关我的事。Whatthedoctorsreallydoubtiswhethermymotherwillrecoverfromtheseriousdiseasesoon.医生怀疑的是我的妈妈是否不久就能从这场重病中恢复过来。【即学活用】语法填空(1)Whetheritwilldousharmorgood_______(remain)tobeseen.(2)Itisestimatedthatabout60percentofdomesticriceconsumptioninChina__(be)comprisedofcropsgeneratedfromYuan’shybridstrains.remainsis(3)Whatwecan’tget_____(seem)betterthanwhatwehave.(4)Whetheritwaspossibletodevelopahybridofself-pollinating______(plant)suchasricewasamatterofgreatdebate.seemsplants