名词性从句一、名词性从句的连接词1．从属连词that，whether和if(1)that，whether，if在从句中不充当任何成分，只起到连接从句的功能。that没有实际意义，而whether，if意为“是否”。(2)whether与if的用法比较二者均可作“是否”讲，都可以引导名词性从句，引导宾语从句时可以互换。Idon’tknowwhether/ifhe’llattendthemeeting.在下列情况下，常用whether，不用if。①whether引导从句可以放于句首。Whetherhecomesornotmakesnodifference.②whether可引导表语从句和同位语从句，if不可。Thequestioniswhetheritisworthtrying.Thequestionwhetherheshouldjointheteamhasnotbeendecidedupon.③whether可以作介词宾语，if则不可。Ihaven’tsettledtheproblemofwhetherI’lllendhimthemoney.④whether后可以加不定式，if不可。Hedidn’tknowwhethertogetmarriedortowait.⑤可以用whether...or引导让步状语从句，意为“无论，不论”，if则不可。Whetheritrainsorsnows，Idon’tcare.2．连接代词引导名词性从句的连接代词有：who，whom，whose，what，which，whatever，whichever，whoever。连接代词在句中既起连接作用，同时又充当主语、宾语、定语、表语等成分。3．连接副词引导名词性从句的连接副词有：when，where，how，why。连接副词在句中既是连接词，又作状语。二、主语从句1．主语从句在复合句中充当主语，大多数主语从句都可以用it作形式主语而把主语从句置于句尾。2．that引导主语从句时可用it作形式主语，that不可省；what引导的主语从句表示“……的东西”时，一般不用it作形式主语；whatever，whoever，whichever一般也不用it作形式主语。Thatshewillsucceediscertain.→Itiscertainthatshewillsucceed.Whatheneedsismoreexperience.(1)It＋系动词＋形容词(necessary，right，likely，unlikely，wrong，important，certain，clear，obvious，strange，normal等)＋that从句Itiscertainthatmostofthefarmershavebroughtinmoremoneybyallmeans.(2)It＋be＋名词(短语)(apity，ashame，goodnews，afact，anhonour，awonder，nowonder等)＋that从句It’snowonderthatyou’veachievedsomuchsuccess.(3)It＋be＋过去分词(said，told，heard，reported，decided，suggested，advised，ordered，remembered，thought，considered，well-known，announced等)＋that从句Itissaidthattheprofessorhasalreadysucceededincarryingouttheexperiment.(4)It＋特殊动词(seem，appear，happen，matter)＋that从句IthappenedtomethatIhadbeenawaywhenhecalled.注意：(1)在“Itisnecessary，important，strange，natural＋that从句”结构中，从句常用“(should＋)动词原形”形式。(2)在“It＋be＋suggested，advised，ordered，requested，insisted，required＋that从句”结构中，that从句应用“(should＋)动词原形”。三、宾语从句1．动词的宾语从句(1)大多数动词(hope，tell，say等)可以带宾语从句。Weallexpectthattheywillwin，formembersoftheirteamarestronger.Idon’tthinkyouareright.Idon’tsupposehecares，doeshe?1(2)动词find，feel，think，consider，make，believe等后有宾语补足语时，则需要it作形式宾语而将that宾语从句后置。Ithinkitnecessarythatwetakeplentyofboiledwatereveryday.(3)有些动词带宾语从句时习惯上需要在宾语从句前加it。这类动词(词组)有hate，enjoy，like，love，dislike，seeto等。Ihateitwhentheytalkwiththeirmouthsfull.2．一般情况下介词后只能用wh类连接词引导宾语从句。Wearetalkingaboutwhetherweadmitstudentsintoourclub.注意：(1)where引导的从句有时也可用作介词的宾语。Wecouldseethetemplequiteclearlyfromwherewelived.(2)that引导的从句作介词的宾语是很少有的，只有在except，in，but等介词后偶尔可能用到。Yourcompositionisquitegoodexceptthattheorganizationisabitloose.3．sure，certain，glad，pleased，happy，surprised等表示“情感”的形容词后也可带宾语从句。I’msurethattheywillmakeitinspiteoftheterribleweather.四、表...
