考点一:名词性从句分类
名词性从句相当于名词,可分别作主句的主语、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、宾语从句和同位从句。
(一)主语从句
1、主语从句在复合句作主语。
e.g. Who will go is not important.
2、用it作形式主语,主语从句放在句末。
e.g. It doesn’t matter so much whether you will come or not.
注意:that引导主语从句时,不能省略。
e.g. That he suddenly fell ill last week made us surprised.
(二)表语从句
1、表语从句在复合句中作表语,位于系动词之后。
e.g. The question was who could go there.
注意:引导表语从句的连接词that有时可省去。
e.g. My idea is (that) we can get more comrades to help in the work.
(三)宾语从句
1、宾语从句在复合句中作宾语。引导宾语从句的连词that一般可省略。
e.g. I hope (that) everything is all right.
2、介词之后的宾语从句,不可用which或if连接,要分别用what或 whether。
e.g. I’m interested in whether you’ve finished the work..
I’m interested in what you’ve said.
注意1:whether与if都可以引导宾语从句,常可互换。但下面情况不能互换。
①宾语从句是否定句时,只用if,不用whether。
e.g. I wonder if it doesn’t rain.
②用if 会引起误解,就要用whether。
e.g. Please let me know whether you want to go.(此句如果把whether改成if,容易当成条件句理解)
③宾语从句中的whether 与or not直接连用,就不能换成if;不直接连用,可换。
e.g. I don’t know whether or not the report is true.
I don’t know whether/ if the report is true or not.
注意2以下情况只能用whether
⑴介词后的宾语从句要用whether引导
⑵whether 可与不定式连用
⑶whether也可引导主语从句、表语从句、同位语从句,让步状语从句,以上从句中均不能换成if
⑷宾语从句中的whether 与or not直接连用
e.g. It depends on whether we have enough money.
They don’t know whether to go there.
(四)同位语从句
同位语从句在句中作某一名词的同位语,一般位于该名词(如:news, fact, idea, suggestion, promise等)之后,说明该名词的具体内容。
e.g. I have no idea when he will be back.
The fact that he had not said anything surprised everybody.
1.同位语从句的功能
同位语从句对名词进一步解释,说明名词的具体内容,一般由that引导。如:
The king’s decision that the prisoner would be set free surprised all the people.
国王作出的这名囚犯释放的决定让人们大吃一惊。
2.同位语在句子中的位置
同位语从句有时可以不紧跟在它所说明的名词后面,而是被别的词隔开。如:
He got the news from Mary that the sports meeting was put off.
他从玛丽那里得知运动会要延期举行。
3.同位语从句与定语从句的区别
1)定语从句中的that既代替先行词,同时在从句中作某个成分(主语或宾语),而同位语从句中的that是连词,只起连接主句与从句的作用,不充当句中任何成分。
2)定语从句是形容词性的,其功能是修饰先行词,对先行词加以限定,描述它的性质或特征;同位语从句是名词性的,其功能是对名词进行补充说明。如:
The news that he told me is that Tom would go abroad next year.
他告诉我的消息是汤姆明年将出国。(第一个that引导的从句是定语从句,that在从句中作宾语)
The news that Tom would go abroad is told by him.