专题九名词性从句概要1.doc

专题九　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。 I don’t know whether/if he’ll attend the meeting. 在下列情况下，常用whether，不用if。 ①whether引导从句可以放于句首。 Whether he comes or not makes no difference. ②whether可引导表语从句和同位语从句，if不可。 The question is whether it is worth trying. The question whether he should join the team has not been decided upon. ③whether可以作介词宾语，if则不可。 I haven’t settled the problem of whether I’ll lend him the money. ④whether后可以加不定式，if不可。 He didn’t know whether to get married or to wait. ⑤可以用whether...or引导让步状语从句，意为“无论，不论”，if则不可。 Whether it rains or snows，I don’t care. 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。 That she will succeed is certain. →It is certain that she will succeed. What he needs is more experience. (1)It＋系动词＋形容词(necessary，right，likely，unlikely，wrong，important，certain，clear，obvious，strange，normal等)＋that从句 It is certain that most of the farmers have brought in more money by all means. (2)It＋be＋名词(短语)(a pity，a shame，good news，a fact，an honour，a wonder，no wonder等)＋that从句 It’s no wonder that you’ve achieved so much success. (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 It is said that the professor has already succeeded in carrying out the experiment. (4)It＋特殊动词(seem，appear，happen，matter)＋that从句 It happened to me that I had been away when he called. 注意：(1)在“It is necessary，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