名词性从句

名词性从句

一、定义：

名词性从句是指在句子中功能相当于名词的从句。通常由that, if/whether, how, what和其它疑问词等充当连接词所引导的从句，其功能同名词一样。

二、类型：主语从句、表语从句、宾语从句、同位语从句

三、引导词

连接词词义功能

that 无词义不作成分，只起连接作用

whether/if 是否不作成分，起连接作用

what, which 什么，哪个作主语、宾语、表语

who, whom, whose 谁，谁的作主语、宾语、定语

when, where, how, why 什么时候，什么地方

怎么样，为什么

作状语、表语

how many/much 多少作定语

how soon/often/long/much 多久，多久一次，多长，作状语

... ... 词义及功能同疑问词

whatever=anything that 无论什么作主语、宾语、表语、定语

whosever=anyone whose 无论谁的作主语、宾语、定语、表语whichever=anything that 无论哪个作宾语、定语、主语、表语

whoever=anyone who 无论谁作主语

whomever=anyone whom 无论谁作宾语

四、考点

1.连接词根据成份和句意确定；

2.语序陈述句的语序；

3.时态主句为一般现在时从句为任何所需的时态，主句为一般过去时从句为过去时的一种，表真理性

的句子除外（一直用一般现在时）。

五、用法

1、主语从句：在复合句中做主句的主语。引导词有连词that (that 不可省),whether（不可用if）; 代词有who, what ,which; 副词when ,where, how, why 等。如:

A. That he is a famous singer is known to us.

(=It is known to us that he is a famous singer. It作形式主语)

B. When he will go to America is not yet fixed.

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

★注意点

▲通常用it 作形式主语的结构

A：It is ＋名词＋从句

It is a fact / an honor / common knowledge/a surprise/a pity that...

B: It is ＋形容词＋从句

It is natural/strange/important/necessary/ that...(should+do)

It is possible/likely/clear/that...

C: It＋不及物动词＋从句

It seems/appears/happens/turns out/occurs to sb. /counts(matters) /that...

D: It ＋过去分词＋从句

It is reported/said/believed/considered/thought/known/announced that...

▲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，主语从句的连接词没有变化。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, 被强调部分指人时也可用

who/whom, 去掉it is …that可以恢复原句。

辨析：

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

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

It was on Monday night that all this happened. ______________________________

It’s me th at he blamed. ______________________________

2.宾语从句：在复合句中做主句的宾语，通常放在主句谓语动词，介词或形容词之后。引导词有连词that (that 常可省略),whether, if 代词有who, whose, what ,which; 副词when ,where, how, why 等。

★注意点

▲动词find，feel，think，consider，make，believe，guess，suppose，assume等后有宾语补足语时，则需要用it作形式宾语，而将that宾语从句后置。如：

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

I have made it a rule that I keep diaries.

▲hate，like，dislike，love, appreciate等表示“喜欢；痛恨”的动词后有宾语补足语时，需要用it作形式宾语而将宾语从句后置。如：

I hate it when they talk with their mouths full of food.

I’ll appreciate it if you can come.

▲宾语从句的否定转移。将think，believe，suppose，expect，imagine等动词后面宾语从句的否定词转移到主句中，即主句的谓语动词用否定式，而从句的谓语动词用肯定式。如：

I don’t think I know yo u. 我想我并不认识你。

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

3、表语从句：在复合句中做主句的表语，常放在be, look, seem等系动词之后。引导词有连词that (that 不可省),whether; 代词有who, what ,which;副词when ,where, how, why 等，此外because，as if等也可引导表语从句。如:

★注意点

▲如果句子的主语是suggestion, advice, order等名词时, 后面引导的表语从句用should+动词原形,should 可省略。如：

A. My advice is that we (should) carry out the plan as soon as possible.

B. His order is that all the soldiers (should) go to bed before the o’clock.

▲注意辨析句式：The reason is that... / The reason for sth.is that…/ The reason why+从句is that…/It is because…如：

A. The reason for his absence is that he hasn’t been informe d. =

B. The reason why______________________ is that he hasn’t been informed.

C. His absence is ____________ he hasn’t been informe d.

▲注意A is to B what C is to D 句式。如：

A. Air is to us what water is to fish.

B. Exercise is to body what knowledge is to mind.

4、同位语从句：在句中起同位语的作用,一般放在名词fact, news, idea, promise, thought, suggestion, advice, evidence, word, truth, possibility, message等之后,用以说明或解释前面的名词。引导词有连that(that 不可以省略)；少数情况下也可用连接副词等。

★注意点

▲如果名词suggestion, advice, order等词后的同位语从句的谓语动词要用should+动词原形,should可省略。▲注意同位语从句和定语从句的区别：

相同点：从句前都有一个名词

不同点：定语从句中关系词代替先行词在从句中做成分;而在同位语从句中连接词不做成分。

定语从句是对前面的名词进行修饰，同位语从句是对前面的名词进行解释说明。

辨析: 1) The news that our team has won the final match is encouraging. ( )