一、名词性从句

概念与分类 

名词性从句相当于名词，可分别在句中作主语、表语、宾语和同位语。因此，名词性从句可分为主语从句、表语从句、宾语从句和同位语从句。  

从属连词that：在从句中不充当任何成分，也没有任何意思，只起连接作用，因此往往可以省略

从属连词if, whether：在从句中不充当任何成分，有意义，不可以省略

连接代词who, whoever, whom, whomever, which, whichever, what, whatever, whose：

在从句中充当成分，有意义，不可以省略

连接副词where, when, why, how：在从句中充当成分，有意义，不可以省略

一、主语从句

１.由从属连词引导的主语从句：

①Whether the country should build a nuclear power station is something we must discuss. 

那个国家是否应该建立核电站……

②That light travels in straight line is known to all .光以直线传播

２.由连接代词引导的主语从句：  

①What we need is more time. 我们所需要的是……

②Whichever book you choose doesn't matter to me.无论你选哪本书……

③Whoever comes will be welcome.无论谁来……

３.由连接副词引导的主语从句：

①When the plane is to take off hasn't been announced.飞机什么时候起飞……

②Where he has been is still a puzzle.他到过哪儿……

③How much water is flowing can be measured easily.水的流量是多少……

4.关于形式主语 it                                                                        ①It + 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…… 

It is likely that….很可能

②It + 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…… 　 

③It + be +名词+ that-从句 　　　

It is common knowledge that…　 ……是常识 　　　

It is a surprise that…　　 令人惊奇的是…… 　　　

It is a fact that…　　　　 事实是……                                                可应用于此句型的名词还有fact / shame / honor / question/pity等。　 

④ It +不及物动词+ that-分句 　　　

It appears that…　　　　　　似乎…… 　　　

It happens that…　　　　　　碰巧…… 　　　

It occurred to me that…　　 我突然想起……   

It doesn't matter whether he likes or not.                                          

二、表语从句

可以接表语从句的连系动词有 be, look, remain, seem 等。

The problem is that millions of people die of illnesses caused by smoking.

……数百万人死于由抽烟引起的疾病

The question remains whether we can win the game…..我们是否能赢得这次比赛 

That's just what I want. ……我想要的

This is where our problem lies. ……我们的问题所在

The difficulty is how we can help smokers kick their habit……我们如何帮助吸烟的人……

值得注意的是：

1. 表语从句的表现形式除了用从属连词，连接代词和连接副词引导以外，还可以由as, as if ，as though引导.

Things were not as they seemed.

It looks as if it is going to rain.好象要下雨了。

2、另外还要注意以下常用的两种结构：The reason why…is that … (而不用 because)

It ( This, That ) is because…

The reason why he was dismissed is that he didn't work hard. 他为什么被开除是因为他工作不努力。

It is because the tobacco companies want to remain in business.

三、同位语从句

同位语从句一般由 that, whether 等连词引导，常放在 advice, doubt, fact, hope, idea, information, message, news, order, possibility, problem, question, reason, truth, word, suggestion.等名词的后面，说明该名词的具体内容。

l. The news that he had landed on the moon spread all over the world. 登陆月球…….

2. I have no idea when he will be back. ……什么时候回来

3. The thought came to him that Mary had probably fallen ill……Mary也许病了

4. He must answer the question whether he agrees to it or not.……是否同意

四、宾语从句

宾语从句可以作及物动词的宾语，介词的宾语，某些形容词的宾语以及非谓语动词的宾语。

1.及物动词后的宾语从句：

She will give whoever needs help a warm support……任何需要帮助的人……

I wonder why she refused my invitation……她为什么拒绝了我的邀请

2.介词后的宾语从句：

I always think of how I can improve my spoken English.我总是在思考如何提高我的口语水平。

The teacher is satisfied with what she has said. 老师对他所说的话很满意。

3.某些形容词后的宾语从句：

I am sure that you will make greater progress in English through hard work.

……通过努力工作，你将取得更大的进步

We are surprised that he has left without saying goodbye to us…….他没有告别就走了

4.非谓语动词后的宾语从句：

Realizing that it was just a difference in custom, the foreigner smiled and said nothing. 

On being asked whether he had had a good time in Australia, he answered "Terrible ". 

5.关于形式宾语it

We must make it clear that anyone who breaks the law will be punished. 

我们必须清楚任何违犯法律的人都将受到惩罚。

I find it necessary that we should ask him for his advice.我发现我们有必要征求他的意见。 

五、名词性从句重难点

1. 在名词性从句中，疑问句要用陈述句的语序。例如：

①Can you make sure ____the gold ring ？（MET90）

A.where Alice had put  B.where had Alice put C.where Alice has put  D.where has Alice put

②You can't imagine __when they received these nice Christmas presents.（94上海）

A.how they were excited  B.how excited they were

C.how excited were they  D.they were how excited

2. 动词 doubt 用在疑问句或否定句中，其后宾语从句常用 that 作连接词；用在肯定句中，连接词用 whether 或 if 皆可，而不用 that。

Do you doubt that he will win ?

I don't doubt that your proposition is wrong . 

He doubt whether I know it . 

3. 否定转移问题。  

①将think, believe, suppose, expect, fancy, guess, imagine等动词后面跟宾语从句时否定转移

I don't think I know you.　我想我并不认识你。 　 

I don' t believe he will come.　我相信他不回来。

We don't expect he will come tonight , will he ? 

注意：若谓语动词为hope,宾语从句中的否定词不能转移。 　

 I hope you weren't ill. 我想你没有生病吧。 

②将seem, appear 等后的从句的否定转移　 

 It doesn't seem that they know where to go. 看来他们不知道往哪去。 　 

 It doesn't appear that we'll have a sunny day tomorrow. 看来我们明天不会碰上好天气。 

4. 主谓一致问题。

What he wanted to see was an end to all the armies of the world．

What I bought were three English books．

5. 语气问题

① 在含有 suggest , order , demand , propose , command , request , insist, desire, require, advise 等表示要求、命令、建议、决定等意义的动词后，that从句常用"should+ 动词原形"的结构

I suggest we (sho