名词性从句一、性质及分类:名词性从句相当于名词,在句中可以作主语、宾语、表语和同位语,所以名词性从句分为主语从句、宾语从句、表语从句和同位语从句
必须注意从句必须用陈述句语序
二、引导词:名词性从句的引导词有:从属连词that,whether,if(一般用于宾语从句中),asif(用于表语从句);连接代词who,whom,whose,what,which,whoever,whomever,whichever,whatever;连接副词when,where,why,how,howmany,howlong,howfar,howoften,howfar,whenever,wherever,however等
三、用法:(一)主语从句的用法:1、that引导主语从句的情况(that引导主语从句在句中无词义,也不充当句子成分):(1)可否省略:that引导的主语从句置于句首时,that不可省略(引导表语从句和同位语从句时也不能省略)
如:Thathewillcomeiscertain
Thatshewaschosenmadeushappy
(2)用it作形式主语,将that引导的真正主语从句置于后面的情况:①“It+be+adj+that从句”
常用于该句型的形容词有:true,clear,obvious,remarkable(值得注意的),probable,(im)possible,interesting,important,certain,(un)likely,astonishing,surprise,doubtful,essential,necessary,important,better,surprising,desirable,impossible,strange,natural,advisable等
如:Itisobviousthatshedoesn’tlikethepla