语法专题9名词性从句.ppt

语法专题九　名词性从句 在句子中起名词作用的从句叫名词性从句(Noun Clauses)。名词性从句的功能相当于名词词组，它在复合句中能担任主语、宾语、表语、同位语、介词宾语等，因此根据它在句中不同的语法功能，名词性从句又可分别称为主语从句、宾语从句、表语从句和同位语从句。 (一)引导名词性从句的连接词 1．引导名词性从句的引导词可分为三类 连接词：(不充当从句的任何成分)that, whether, if 连接代词：what, whatever, who, whoever, whom, whose, which 连接副词：when, where, how, why 2．不可省略的引导词 (1)介词后的引导词不可省略。 (2)引导主语从句和同位语从句的引导词不可省略。 如：That he was chosen president made us very happy. We heard the news that our team had won first prize. 3．whether与if均为“是否”的意思。但在下列情况下，whether不能被if所取代 (1)引导主语从句(包括从句在句首的位置)应当用whether，不用if，如： Whether our team will win remains a problem. Whether he will come, I am not sure. (2)引导表语从句用whether，不用if，如： The question is whether you have enough money now. (3)whether可以引导从句作介词的宾语，而if则不能，如： I’m not interested in whether they’ll come or not. It depends on whether we have got enough time. (4)whether可以直接和动词不定式连用，而if则不能，如： I didn’t know whether to wait or to leave. Mike hasn’t decided whether to make a telephone call or not. (5)引导同位语从句用whether，不用if，如： The news whether they will attend the party is not known yet. 大部分引导词引导的主语从句都可置于句末，前面用it充当形式主语。 如：It is not decided yet whether the meeting will be held this evening. (二)名词性that－从句 1．由从属连词that引导的从句叫做名词性that－从句。that只起连接作用，在从句中不担当任何成分，本身也没有词义。 名词性that－从句在句中能充当主语、宾语、表语、同位语和形容词宾语，如： 主语：That he got the first prize is not just a joke. 宾语：John said that he was leaving for London on Wednesday. 表语：The fact is that we can’t afford to buy the house. 同位语：The fact that he has not been seen recently disturbs everyone in his office. 形容词宾语：I am glad that you are satisfied with your job. 2．that－从句作主语通常用it作形式主语，而将that－从句置于句末，如： It is quite clear that Taiwan belongs to China. It’s a pity that you should have to leave on such an occasion. 用it作形式主语的that－从句有以下四种不同的搭配关系： (1)It＋be＋形容词＋that－从句 It is necessary that...有必要……。 It is important that...重要的是……。 It is obvious that...很明显……。 (2)It＋be＋－ed分词＋that－从句 It is believed that...人们相信……。 It is known to all that...众所周知……。 It has been decided that...已决定……。 (3)It＋be＋名词＋that－从句 It is a