主语从句详细讲解.doc

主语从句 「、概念：在复合句中起主语作用的从句叫主语从句 (一) 连接词从属连词 关系代词 关系副词that、whether；who, what, which , whom, whose, whatever, whoever, whomever, whichever whe n, where, how, why, however, whe never, whereve等 ；主语从句的引导词对应的简单句类型引导词是否作成分引导词是否可省略连词that陈述句不作成分，也没有实.、、八 意在句首时不可省略连词 whether一般疑问句whether在从句中不作 成分，但具有“是否” 的意义不可省略连接畐词 when, where, why, how;连接代词 who, whom, what, which, whose特殊疑问句(1) whe n, where, why, how在从句作状语；(2) who, whom, what 从句中作主语、宾语 或表语；(3) which, whose 在从 句中作定语，后面接 名词连用不可省略，因为它们 即作成分，又有意义1.从属连词that，whether引导的主语从句。

从属连词that，whether在主语从句中的作用只是引导主语从句，在从句中不担任成分，不能 省略例: they will go is certa in. she will come or not is still a questi on. shesco ming or not does n't matter too much.it作形式主语，而把主语从句放2. it作形式主语引导主语从句 如果主语从句太长，为避免句子结构头重脚轻，我们可用在主句谓语部分之后用作it作形式主语的结构：It 'obvious that -显而易见…It '(im)possible…(不)可能It 'stra nge that ••奇怪的是 It 'a fact that … 事实是 It 'a won der that- 不足为奇 It 'a shame that •真是可耻…It happened that -碰巧 It turns out that- ••结果…⑴It is/was +形容词+that从句It'natural that… 很自然 It 'fortunate that … 幸运的是It 'unlikely that…不可能(2) lt is/was + 名词 +that 从句It 'a pity that… 遗憾的是 It 'good n ews that…是好消息 It 'an honour that… 非常荣幸 It 'com mon kno wledge that-.. 是常识(3) It +不及物动词+that从句It seems that … 似乎 It appears that…看来 (4) lt is/was +过去分词+that从句It 'not known that 不得而知 It 'said that …据说 It 'reported that… 据报道 It' decided that ••尚未决定It 'believed that… 据认为 It 'ann ou need that…据宣布 It suddenly struck me (occur to me that… 我突然想至U (感觉至U) ⑸其他It doesn'tmatter… 是无关紧要的It makes no differenee… 毫无区另S It is of little con seque nee that …无关紧要［随堂练］It is a pity she has made such a mistake她犯这样的错误是令人遗憾的事。

It's strange he did'come yesterday.他昨天没来是很奇怪的It is reported the nu mber of wild ani mals in Africa is decreas ing.据报导非洲野生动物的数量正在减少It is said there was a terrible pla ne crash this morni ng.据说今天早上有一起可怕的飞机坠毁事故1主语从句在句首时，必须由连接词引导，不能省略这些连接词；但是如果用it作形式主语, 而把主语从句放在句末时，从属连词 that在口语中可以省略误：They should like each other is natural.正： That they should like each other is n atural.正: It is natural that they should like each other.2） 如果主语从句放在句首，不能用if引导，但是如果用it作形式主语，而把主语从句放在 句末时，也可以用if引导.误：If Mary really heard him is really doubtful.正: It was doubtful if Mary really heard him.3） 用于 It is important / natural / necessary / impossible that..句型中，主语从句应使用虚拟语气谓语动词用 should +动词原形”的形式或直接用动词原形。

4） 在 It + be+suggested/advised/ordered/requested/insisted/require中，that从句的谓语也应该用 “should +动词原形”的形式,should有时可以省略［随堂练］Does matter if he can't fin ish the job on time?A. this B. that C. he D. it is a fact that En glish is being accepted as an intern ati on al la nguage.A. There B. This C. That D. ItIt is n ecessary that a college stude nt at least a foreig n Ian guage.A. masters B. should master C. mastered D. will master is known to everybody, the moon travels round the earth once every month.A. It B. As C. That D. What3. 由连接代词引导的主语从句。

1) 连接代词 who, what, which, whom, whose, whatever, whoever, whomever, whicheve等，引 导主语从句时，它们分别在从句中担任主语、宾语或定语，不能省略 leaves the room last ought to turn off the lights.走得最晚的应当关灯 you have done might do harm to other people. 你的行为可能伤害别人 he said at the meeti ng ast oni shed everybody prese nt.他在会议上的发言时所有入会者吃惊 made the long dista nee call is not importa nt. 谁打的长途并不重要2) what引导主语从句“ 的东西/事情”时，可用来表示the thing(s) which这种意思，引导从句，表示一样东西与一件事情，这种用法的 what称为关系代词型what，who, whom，which，what可以和ever构成合成词，和what 一样引导从句，ever起强调作用。

这些关系词 在句子中充当成分，所以不能省略此类主语从句不能用形式主语 it引导 (二The thing which I n eed) is a mobile pho ne.我所需要的是一部移动 leaves the office (=A ny one who leaves the office) should tell me.无论是谁离开办公室都应该告诉我4. 关系副词引导的主语从句连接畐词有 when, where, why, how, however, whenever, whereve等引导主语从句时，它们在从 句中担任状语，不能省略此类主语从句可以转换为以 it作形式主语的句子 he didntcome here is not clear to anyone. 他为什么没来谁也不清楚 a telepho ne works is a questi on which not every one can an swer.是怎样工作的，这个问题并不是每个人都能回答 she has gone is not known yet. 她去了哪儿，还不知道 they will start has not bee n decided yet. 他们何时动身还未定下来。

he did it did n't c on cern me. 他为什么做这件事与我无关二) 位置主语从句不可位于句首的四种情况1)含主语从句的复合句是疑问句、感叹句时，主语从句不可提前，用引导词 it作形式主语Is it really true that he has gone abroad? 他真的出国了吗？How surprisi ng it was that he failed in the exam! 真令人惊奇，他考试没有及格！(2)It is said, reported,…结构中的主语从句不可提前It 'said that the play is very in teresti ng. 据说戏居 U很有趣It 'reported that the highway will be ope ned to traffic n ext week.据报道，高速路下周通车3) It happe ns, occurs…结构中的主语从句不可提前It occurred to her that she had forgotten to lock the door. 她突然想起忘了锁门It happe ned that I met him in the street. 我恰巧在大街上遇到了他。

4) It does n'tmatter how, whether or n ot…结构中的主语从句不可提前 It doesn'tmatter whether he likes it or n ot. 他喜欢与否无关紧要It does n'tmatter how he will come. 他怎么来不重要三) 主语从句的时态和单复数1. 主语从句的时态：不受主句的时态影响和限制What caused the accide nt remai ns unknown 事故发生的原因仍未清楚Who will be our mo nitor has n'tbeen decidedyet.谁将。