名词性从句考点精析
2016-05-30胡菊英胡俊
胡菊英 胡俊
名词性从句，是指在复合句中性质相当于名词的从句。它包括主语从句、宾语从句、表语从句和同位语从句。历年全国各省市高考试题对名词性从句都考查较多。
例1 （2013·重庆卷）That struck me most in the movie was the fathers deep love for his son.
解析 That→What。此题考查主语从句，what在从句中充当主语。
例2 （2015·全国卷Ⅱ）After looking at the toy for some time， he turned around and found where his parents were missing.
解析 where→that，或去掉where。此题考查宾语从句，that在句中不充当任何成分，可以省略。
例3 （2014·北京卷） The best moment for the football star was _____ he scored the winning goal.
解析 when。考查表语从句。句意：对一个足球明星来说，进球得分的时刻是最好的时刻。根据题干中的moment一词推断，后面说的应该是“……的时候”。
例4 （2012·浙江卷） I made a promise to myself _______ this year， my first year in high school， would be different.
解析 that。此题考查同位语从句。句意：我对自己作出了承诺，今年——我读中学的第一年——将会有所不同。that引导的从句是对promise进行解释和说明，that在句中不充当任何成分，通常不能省略。
纵观历年高考试题，我们可以发现名词性从句考查的焦点主要在以下几个方面：
[that与what的区别]
1. 连词that在引导名词性从句时本身没有意义，在从句中不充当任何句子成分。
that引导主语从句位于句首时，that无意义，但是不可省略。如：That you didnt know the rules wont be an excuse for your failure.
that引导表语从句时，一般不省略。如：My decision is that all of us are to start at 6 oclock tomorrow morning.
that引导同位语从句时，应在某些抽象名词如fact， hope， desire， thought， suggestion， idea， news， problem， possibility等后，对前面的名词起补充说明的作用，在从句中不充当任何成分，一般不省略。如：Modern science has given clear evidence that smoking can lead to many diseases.
that引导宾语从句时，在句中不充当任何成分，在口语或非正式的文体中常被省去，但如果从句是并列句，第二个分句前的that不可省略。如：He said （that） he liked rain very much and that he wouldnt use an umbrella when it was raining.
2. 连词what引导名词性从句时，what在从句中充当主语、宾语、表语等。如：
What matters most in learning English is enough practice. （主语）
What he considered a great proposal was turned down by the boss. （宾语）
China is no longer what she used to be. （表语）
[名词性从句的语序、时态问题]
由who， whom， which， whose， what， when， where， why， how， whoever， whichever等关联词引导的名词性从句，应注意句子要用陈述语序。如：
Scientists study how human brains work to make computers.
I want to know what he has told you.
She always thinks of how she can work well.
在含有宾语从句的主从复合句中，当主句的谓语动词是过去时态时，从句须用表示过去的某种时态；当宾语从句表述的是客观事实、科学真理以及格言等时，其时态不受主句限制，常用一般现在时；当主句的时态是一般现在时、现在进行时、现在完成时等，从句可根据情况选用各种适合的时态。如：
He asked when they would go to the party.
The teacher told us that light travels faster than sound.
Do you know he has gone to Beijing？
[it作形式主语/宾语的用法]
1. that引导主语从句时，常用it作形式主语，常见的句型有：
it+be+形容词（obvious， natural， surprising， good， wonderful， possible， etc.）+that从句。如：It is obvious that they should get well prepared for their future.
it+be+名词词组（no wonder， an honor， a good thing， a pity）+that从句。如：He plays computers all day. It is no wonder that he failed to pass the test.
it+be+过去分词（said， reported， thought， expected， announced， etc.）+that从句。如：It is decided that the meeting has been put off till next Monday.
2. 特殊疑问词引导主语从句，常用it作形式主语。如：It makes no difference where we shall have the meeting.
3. 在可以接复合宾语的动词之后，如think， make， consider等，可以用it作形式宾语。如：He has made it clear that he will not give in.
[whether与if的区别]
whether和if在宾语从句中经常可以互换，但下列情况常用whether，不用if。
1. 与or或or not连用时只能用whether。如：He must answer the question whether he agrees to it or not.
2. 从句作介词宾语时只能用whether。如：It depends on whether you can do the work well.
3. 在引导主语从句、表语从句和同位语从句时一般用whether不用if。如：
It doesnt matter whether you pay by cash or credit card in this store.
The question is whether it is worth trying.
[“疑问词+ever”引导的名词性从句]
1. “疑问词+ever”可引导名词性从句，在主从句中要充当一定的成分。whoever与whatever表示泛指，意为“无论谁”“无论什么”；whichever表示在特定范围内选择，意为“无论……的哪一个/哪一些”。如：
There are various things on sale， so you can choose whatever interests you.
We have plenty of books. You may take whichever you like.
2. “疑问词+ever”还可以引导让步状语从句。
3. “no matter+疑问词”只能引导让步状语从句。
[名词性从句中的虚拟语气]
1. 表示“建议、要求、请求或命令”等意义的词出现在主语、表语和同位语从句中时，谓语要用“should+动词原形”的虚拟结构，should可以省略。如：
Its suggested that one （should） take exercise every day. （主语从句）
His suggestion is that you （should） take measures at once. （表语从句）
He made a suggestion that you （should） take measures at once. （同位语从句）
2. 在主语从句中，表示“做某事很重要、很必要、很遗憾或者很奇怪”时，谓语也要用“should +动词原形”，should可以省略。如：
Its important/necessary that we （should） learn English well.
Its a pity that he （should） be late again.
[考查同位语从句与定语从句的区别]
同位语从句是对前面名词的内容作进一步的解释、说明，引导词that只起引导作用，在句中不作任何成分，一般不可省略；定语从句是对前面名词进行修饰、限制，引导词在句中作一定的句子成分，作宾语时可以省略。如：
The news that they had won the game soon spread over the whole school.
他们赢得比赛的消息很快就传遍了整个学校。（同位语从句，进一步解释the news的内容）
The news （that） you told me yesterday was really disappointing.
你昨天告诉我的消息真的很令人失望。（定语从句，它指的是“你昨天告诉我的那个消息”）
