(教师用)高中名词性从句讲解

专题7 ：名词性从句

一、概念

在句子中起名词作用的句子叫名词性从句。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, 因此可分别称为主语从句、宾语从句、表语从句和同位语从句。主要考查语序问题、连接词选用、时态的呼应等

Who will win the match is still unknown.

I want to know what he has told you.

The fact is that we have lost the game.

The news that we won the game is exciting.

2. 引导名词性从句的连接词可分为三类:

从属连词：that, whether, if 不充当从句的任何成分

连接代词: what, whatever, who, whoever, whom, whose, which, whichever. （作主、宾、表、补）

连接副词:

when, where, how, why, however, wherever（状）

主语从句的用法

一、主语从句在复合句中作主语, 它可以位于句首, 但常见的主语从句多放在句末,句首则用形式主语it。

1．That the earth is round is true.

= It is true that the earth is round

2. Whether he will come hasn’t been decided.

= It hasn’t been decided whether he will come.

注意: 连词that, whether在从句中不担任句子成分,只起连接作用,不能省略(注: if不可用来引导主语从句）

When he will go to America is not yet fixed.

(It is not yet fixed when he will go to America.)

Whoever leaves the room last should close the door.

Whatever we do must be in the interests of the people.

3.常见的it作形式主语的结构

二、it 作形式主语和it引导强调句的比较

it 作形式主语代替主语从句,主要是为了平衡句子结构, 主语从句的连接词有变化。而it引导的强调句则是对句子某一部分进行强调,无论强调的是什么成分,都可用连词that。被强调部分指人是也可用who/whom。例如:

◆It is a pity that you didn’t go to see the film.

◆It doesn’t interest me whether you succeed or not.

◆It is in the morning that the murder took place.

◆It is John that broke the window.

宾语从句的用法

句子结构：

主句+ 连接词(引导词) + 宾语从句；在think, believe, suppose, expect 等动词之后,宾语从句中谓语的否定常转移到主句的谓语上。

I don’t believe he will go.

We don’t expect he is coming.

I don’t think he can do it, can he?

You /They don’t think he can do it ,do they?

在接复合宾语的句子中, 为了保持句子平衡, 用it 作形式宾语,将从句放于句尾, 常接复合宾语的动词有: make, find, see, hear, feel, think...

I think it necessary that we take plenty of hot water every day.

I think it a pity to waste the food

表语从句的用法

在复合句中用作表语的从句是表语从句, 引导表语从句的关联词与引导主语从句的关联词大致一样,表语从句位于连系动词后,有时用as if引导。其基本结构为:主语+ 系动词+ that 从句。

That’s what we should do.

That’s why I want to see you.

The reason for my absence was that I was ill.

1. be, seem, look等动词后均可跟表语从句：

My suggestion is that we should go shopping.

It seems that it is going to rain

2. as if, because 也可引导表语从句。

It looks as if it’s going to rain.

It was because I got up late.

3. 在非正式文体中,引导表语从句的that可以省略。如:

The trouble is (that) he is ill

注意:在表语从句中,当reason做主语时, 引导词只能用that,不能用because,如:他迟到的原因是因为他没有赶上早班车。The reason why he was late was that he didn’t catch the early bus.

同位语从句的用法

在句中起同位语的作用.一般放在名词fact , news , idea , promise, thought , suggestion,truth , hope , problem, information, belief, doubt, question dream advice, proof decision等之后,用以说明或解释前面的名词.

1.The question whether we need more time to do the work has not been discussed.

2.I have no idea when they will go.