名词性从句名词性从句包括：主语从句、表语从句、宾语从句、同位语从句名词性从句和名词一样，在句中可担任主语，表语、宾语、同位语引导名词性从句的连接词有连接代词who,whose,whom,what,which连接副词when,where,why,how连接词that,whether,if,asif连接代词和连接副词在句中充当句子成分，连接词在句中不充当句子成分I.主语从句在句子中担当主语的是一个从句，这个从句就叫做主语从句。主语从句可以位于句首，但常见的主语从句多放在句末，句首则用形式主语it。例如：1.Whowillgoisnotimportant.2.Whatweneedismoretime.3.Thathesuddenlyfellilllastweekmadeussurprised.4.Thattheearthisroundistrue.=Itistruethattheearthisround.5.Whetherhewillcomehasn’tbeendecided.=Ithasn’tbeendecidedwhetherhewillcome.【注意】连词that,whether在从句中不担任句子成分，只起连接作用，不能省略。并且whether引导主语从句时不能用if代替。6.Wholetoutthenewsremainedunknown.=Itremainedunknownwholetoutthenews.7.Howthishappenedisstillaquestion.8.Itisnotclearwhenwewillstart.9.Whyhedidn’tcomehereisnotcleartoanyone.=Itisnotcleartoanyonewhyhedidn’tcomehere.10.Who/whichisrightisn’tknowntous.【注意】who,which,how,when,where,why在所引导的主语从句中可担任主语，宾语，状语，不能省略。可以用形式主语it引导。另外，有的“It...＋主语从句”已成为固定结构。如：a.Itis＋名词＋从句Itisapitythatwecan’tgo.b.Itis＋形容词＋从句ItisclearthatTomhasreturned.c.Itis＋过去分词＋从句Itissaid/reported/believed/known...（翻译）据报道一家网吧昨夜着火了。ItwasreportedthattheNetBarcaughtfirelastnight.II.表语从句在复合句中用作表语的从句是表语从句。它一般位于主句系动词之后。That’swhatweshoulddo.ThereasonformyabsencewasthatIwasill.（翻译）那就是他为什么今早没赶上火车。That’swhyhedidn’tcatchthetrainthismorning.（翻译）那是因为他今早起晚了。That’sbecausehegotuplatethismorning.1.be,seem,look,sound,appear等动词后均可跟表语从句：Mysuggestionisthatweshouldgoshopping.Itseemsthatitisgoingtorain.2.as,asif/though也可引导表语从句Itlooksasifit’sgoingtorain.Helookedjustashehadlookedtenyearsbefore.Itsoundsasifsomeoneisknockingatthedoor.1【注意】在表语从句中，当reason做主语时，引导词只能用that，不能用because。如：Thereasonwhyhewaslatewasthathedidn’tcatchtheearlybus.III.宾语从句在句子中担当宾语的是一个从句，这个从句就叫做宾语从句。1.作动词宾语Idon’tknowwhatIwasthinkingof.IwonderifImightgiveyouanecklace.Iexpect(that)IshallbebackonSunday.【注意】在口语中，that引导宾语从句时常常省略。但两个that从句并列时后边的that一般不省略。若有补语，则宾语从句要放到补语之后，在宾补前用形式宾语it。Hedoesn’twantittobeknownthatheisgoingaway.Iconsideritnecessarythatheshoulddoitagain.【否定前移】当主句是I/wethink,suppose,expect,believe,guess,imagine时，其后的宾语从句如果是否定的，常常把否定词not从从句中移到主句中。Idon’tbelievetheywillwinthegame.Idon’tthinkyouwillhelpmewiththechemistryexperiment,willyou?Wedon’texpectheiscoming.【注】此种用法主句的主语必须是第一人称I或we。而且它的反意疑问句的助动词由从句的助动词来定。Idon’tthinkhecandoit,canhe?Idon’tthinkyouareright,areyou?在suggestinsist,order,demand,request,require,command,propose,desire等表示建议、命令、要求、欲望动词后面的宾语从句中，用虚拟语气，即should+动词原形，should常被省略。如Iinsistedthathe(should)doitatonce.Shesuggestedthatthework(should)befinishedatonce.2.作介词宾语TheteacherissatisfiedwithwhatIsaid.Yoursuccesswilllargelydependuponwhatyoudoandhowyoudoit.Hewasdeeplydispleasedbywhathadoccurredthatday.3.作afraid,glad,certain,sure等形容词的宾语I’...
