名词性从句精讲精练名词往往在句中充当主语，宾语，表语和同位语。

在复合句中，代替名词充当主语，宾语，表语和同位语的句子统称为名词性从句。

名词性从句分为：主语从句、宾语从句、表语从句、同位语从句。

（一）引导名词性从句的连接词引导名词性从句的连接词可分为五类：a.连词：that（无任何词意，不作成分，只起连接作用，宾语从句中常可省略）1) My hope is that she will soon be well again. (表语从句)我的希望是她能很快康复。

2) Everybody hopes that she will soon be well again.（宾语从句）大家都希望她能很快康复。

3) That she will soon be well again is our hope.（主语从句）她能很快康复是我们的希望。

b. whether, if（均表示“是否”表明从句内容的不确定性，不作成分）1) Whether he is coming or not doesn’t matter too much.(主语从句，不能用if)2) I went in and asked if/whether they had a cheap suit.3) I wonder whether/if he will come in such bad weather.c. 连接代词：what, whatever, which, whichever, (在从句中作主语，宾语，表语，指物)1) ____he need is more time.显然，主语从句：he是主语，谓语动词need缺宾语，因此应填what.2) Tell us ___you saw and heard during your visit to that university.3) This is not ___I want.4) ____some people are against is ___other people are for.5) The question is which team will win.6) I have two apples, I don’t know which you want.归纳：what一般用于不知道内容或范围的句子；which“哪一个……”一般用于给出内容或范围的句子。

可作主语，宾语，表语，还可作定语。

d. who, whoever, whom, whomever, whose（在从句中作主语，宾语，表语，定语，指人）1) Who will give us a lecture is unknown.2) The question is who will come here.e. 连接副词：when, where, how, why, whenever, however, wherever (在从句中作状语)1) I have no idea how he learned about it.2) Where she has gone is not known yet.3) When he will start is not known yet.4) This is why he is late.注意：连接代词和连接副词在句中既保留自己的疑问含义、又起连接作用，在从句中充当从句的成分。

（二）具体分类一）主语从句在复合句中作主语的从句叫主语从句。

1) That you are leaving is a pity.你要走，真遗憾。

2) Whether the football game will be played depends on the weather.足球比赛是否举行将视天气而定。

3) What he wants to tell us is not clear.他要跟我们说什么，还不清楚。

4) Who will win the match is still unknown.谁能赢得这场比赛还不得而知。

5) Where the English evening will be held has not yet been announced.英语晚会将在哪里举行，还没有宣布。

6) It is known to us how he became a writer.我们都知道他是如何成为一名作家的。

有时为避免句子头重脚轻，常用形式主语it代替主语从句作形式主语放于句首，而把主语从句置于句末。

主语从句后的谓语动词一般用单数形式。

常用句型如下：（1）It + be + 名词+ that从句① It’s a pity that we can’t go.很遗憾我们不能去。

② It is a fact that English is being accepted as an international language.英语正在被人们接受为国际语言，这是事实。

③ It is no wonder that he is not hungry; he has been eating sweets all day.难怪他不饿，他整天在吃糖果。

（2）It + be + 形容词+ that从句① It is certain that she will do well in the exam.毫无疑问她考试成绩会很好。

② It is probable that he told her everything.很可能他把一切都告诉她了。

③ Is it true that the scientist will give us a lecture.下周那位科学家将给我们作报告是真的吗？（3）It + be + 动词的过去分词+ that从句① It is said that Mr. Green has arrived in Beijing.据说格林先生已经到了北京。

② It is reported that China has sent another man-made earth satellite into orbit.据报道中国又成功地将一颗人造地球卫星发射进入轨道。

（4）It + 不及物动词+ that 从句① It seems that Alice is not coming to the party at all.爱丽丝似乎不来参加晚会。

② It happened that I was out that day.碰巧那天我外出了。

（5）其他情况① It doesn’t matter wh ether she will come or not.她是否来无关紧要。

② It makes no difference where we shall have the meeting.我们在哪里开会毫无区别。

③ It suddenly occurred to her that she had forgotten to lock the door.她突然想到,她忘记锁门了。

另注意：在主语从句中用来表示惊奇、不相信、惋惜、理应如此等语气时，谓语动词要用虚拟语气“(should)+do”，常用的句型有：a. It is necessary (important, natural, strange, funny, surprising etc.) that …It is important and necessary that we(should)keep the balance of nature.我们要维持生态平衡，这很重要而且是必不可少的。

b. It is a pity (a shame, no wonder, etc.) that…It is a pity that you (should) miss such a good chance.真遗憾你竟然失去这么好的机会。

c. It is suggested (requested, proposed, desired, etc.) that…It’s suggested that we (should) do the experiment a second time.有人建议我们再做一次实验。

Exercises:1. ____ is power is a famous saying known to us all.A. What knowledgeB. How knowledgeC. That knowledgeD. Where knowledge2. ___we can’t get seems better than ___we have.A. What, whatB. What, thatC. That, thatD. That, what3. ___troubles me is ___I can’t learn all these English idioms b y heart.A. That, thatB. What, what C, That, what D. What, that4. ___you need to improve your listening is more practice.A. ThatB. WhatC. WhyD. How5. Y our skirt is really splendid, but ___we actually need is not a skirt but a new pair of shoes.A. thatB. whatC. whetherD. how6. ___she couldn’t understand was ___fewer and fewer students showed interest in her lessons.A. What; whyB. That; whatC. What; becauseD. Why; because答案：1. C 2. A 3. D 4. B 5. B 6. A二）表语从句在复合句中作表语的从句叫表语从句。

其基本结构为：主语+ 系动词+ that从句。

表语从句位于连系动词后，可接表语从句的连系动词有：be, look, seem, sound, appear，remain 等。

1) The fact is that we have lost the game.事实是我们已经输了这场比赛。

2) That’s just what I want.那正是我想要的。

3) The question is whether they will be able to help us.问题是他们能否帮我们。