高一英语同步练习:必修3Unit4Astronomy:thescienceofthestars第3课时Grammar基础练习一.语法知识:主语从句:做主语用的名词性从句,因其在复合句中做主语,又称主语从句,引导主语从句的有从属连词that,whether,连接代词who,what,which,连接副词when,where,how,why等。1..连接词:1)从属连词:that,whether等.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由whether及其他连词引导的主语从句放在句首,句后都可。Whetheritwillpleasethemisnoteasytosay.Whethershe’scomingornotdoesn’tmattertoomuch.2)连接代词who,what,which,whatever,whichever,whoeverWhatseemseasytosomepeopleseemsdifficulttoothers.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,而把主语从句放在句末,常用下面几种句型。1)It+be+表语+主语从句1表语:(名词,形容词,过去分词)Itisapitythatwecan’tgo.Itisnosurprisethatourteamshouldhavewonthegame.ItisanhonourthatIwasinvitedtoattendthemeeting.Itiscertainthatshewilldowellinherexam.ItistruethatItoldhereverything.ItissaidthatMr.GreenhasarrivedinBeijing.ItisreportedthatChinahassentanothermanmadeearthsatelliteintoorbit.2)It+不及物动词或短语+主语从句Itseemed(happened,doesn’tmatter,hasturnedout)that…Ithappensthattheywereabsent.ItseemsthatAliceisnotcomingtothepartyatall.Itdoesn’tmatterwhethershewillcomeornot.Itmakesnodifferencewhereweshallhavethemeeting.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...