英语名词性从句(详细讲解).docVIP

名词性从句 第一部分：语法讲解 名词从句是指在句子中起名词作用的各种从句。根据它们在句子中所起的作用不同，名词从句可以分为主语从句、表语从句、宾语从句和同位语从句。 引导名词性从句的常用连词： 连词that 对应于陈述句 that在从句中不作成分 连词whether, if 对应于一般疑问句 whether,if在从句中不作成分 连接副词when, where, why, how; 连接代词who, whom, what , which, whose 对应于特殊疑问句 when, where, why, how作状语； who, whom, what作主语、宾语或表语； which,whose作定语，后面接名词连用。 如：That the earth is round is a fact. I don’t know if he needs my help. I don’t know where he went. 主语从句 1）主语从句在句中作主语。 如：Whether he will accept the invitation is not clear.他是否会接受邀请还不清楚。 When he left is unknown.他什么时候离开还不知道。 That he will come to the discussion is certain.他来参加讨论是肯定无疑的。 2）主语从句放在句首，句子常常显得比较笨重，因此常把它移至句子末尾，而用it作形式上的主语。 如：It is strange that she did not come yesterday. 很奇怪，她昨天没有来。 It has not been announced when the plane is to take off.飞机何时起飞还没有宣布。 It is a pity that Mr.Brown can’t attend our English meeting.真可惜，布朗先生不能出席我们的英语晚会。 3）有些用“it”作形式主语的主语从句结构已形成固定的用法。 It is +名词+从句 如：It is a fact that…事实是…… It is common knowledge that… ……是常识 It is +形容词+that从句 如：It is necessary that… 有必要…… It is likely that… 有可能…… It is important that… 重要的是…… It is +过去分词+从句 如：It is said that… 据说…… It is reported that … 据报道…… It is well known that… 众所周知…… It is estimated that… 据估计…… It +不及物动词+从句 如：It seems that … 好像…… It happened that… 碰巧…… 如：It is estimated that millions of galaxies exist in the vast space outside the Milk Way.据估计，在银河系之外的辽阔星空中存在着千百万个星系。 表语从句 表语从句在句中作表语，它位于主句中的连系动词后面。结构：主语+连系动词+表语从句。常用的这类连系动词be, seem, remain, look等。 如：The question is whether we can finish our work by tomorrow evening.问题在于我们能不能在明天晚上以前完成这项工作。 That is why she had a day-off yesterday.这就是她昨天请假的原因。 Things are not always as they seem to be.事情并不总是如其表象。 It looked as if it is going to snow.看起来要下雪了。 It may be because he is too young.这可能是因为他太年轻了。 4．宾语从句：宾语从句可以作谓语动词的宾语，也可以作介词和非限定动词（动词不定式、动名词、分词）和某些形容词的宾语。 作动词的宾语 如：I know that he is friendly and hospitable.我知道他很友好而且好客。 I asked him if he is sure he knows what he is doing? 我问他是否确信知道自己在做什么？ 作介词宾语 如： He was interested in whatever he saw he