名词性从句包括主语从句、表语从句、宾语从句和同位语从句。
主语从句
主语从句在句中作主语。它是高中英语语法学习中的难点,也是高考考查的重点。掌握好这种从句,关键是要掌握引导主语从句的连接词的选用、语序问题及主谓一致的问题。
助记歌诀:
整个句子作主语,后面紧跟单谓语;
陈述莫忘加 that,语序如同陈述句。
1.连接词的选用
(1)由连词 that 引导的主语从句。that 在引导的主语从句中只
起连接作用,它本身无具体含义,在从句中不充当任何句子成分。that 放在句首时,不能省略。that 从句作主语时,常用 it 作形式主语。
常见的句型是:
①“It is + 形容词/名词 + that 从句”
②“It is+过去分词(said,hoped, reported, known, believed等)+ that 从句”。如:
That the earth turns around the sun is known to all.=It is known to all that the earth turns around the sun.众所周知,地球绕着太阳转。
That he has gone abroad for further education is clear to us all.=It is clear to us all that he has gone abroad for further edu- cation.我们都知道他出国深造去了。
(2)由连接代词 what 引导的主语从句。what 引导主语从句时本身有词义,意为“所……的”,相当于 the thing that,everything that,all that 等。在从句中充当主语、宾语、表语,而且不能省略。如:
What seems easy to some people seems difficult to others.对某些人好像很容易的事情,对别人可能很困难。
What we can't get seems better than what we have.我们不能得到的似乎比我们拥有的更好。
What you need is more practice. 你所需要的是更多的训练。
(3)由连接副词引导的主语从句
Where the meeting will be held hasn't been decided.会议在哪儿召开还没有确定。
When he will return isn't clear to us.他什么时候回来,我们不清楚。
Why they are reducing price does not matter.他们为什么减价并不重要。
(4)“疑问词+ever”构成的复合连接词引导的主语从句。如:
Whoever breaks the law should be punished.不管谁触犯了法律都应受到惩罚。
Whichever of you gets here first will get the prize.你们谁第一个到达这里,谁就获得奖品。
Whatever you say will interest us all.不管你说什么我们都觉得有趣。
Whatever I have done is only for you.我所做的一切都是为了你。
Whatever he said was true.他所说的一切都是真实的。
However you do it is all right with me.你无论怎样做这件事对我来说都行。
注:whatever/whoever/whomever/whichever 既可以引导名词性从句,也可以引导让步状语从句。引导让步状语从句时,等同于 no matter what/who/whom/which.
Whatever you say,I won't believe you.=No matter what you say, I won't believe you.不论你说什么,我都不会相信。
Whoever it is,I don't want to see him.=No matter who it is,I don't want to see him.不管是谁,我都不想见。
特别提示:whatever,whoever,whomever,whichever 引导名词性从句时,不能换用 no matter what/who/whom/which。
We wrote a letter of thanks to whoever had helped us.凡是帮助过我们的,我们都寄去了感谢信。(whoever 不可换用 no matter who,也不能用 whomever 代替)
(5)其他
Who will go there is not important. 谁去那儿不重要。
Which team will win the championship is uncertain.哪个队会得冠军还说不准。
Whether we'll go camping tomorrow depends on the weather.我们明天去不去野营还得看天气。
Whether you succeed in the end will mainly depend on what you do and how you do it.最终你是否能取得成功还得看你做了什么,怎么做的。
(6)it作形式主语
that所引导的主语从句常放到句子后部,由代词it作形式主语。如:
It makes everyone happy that the girl is still alive.那女孩还活着让所有的人都很高兴。
It is impossible that I go and attend the meeting.我不可能去参加会议。
在itis a pity,it is a shame,it is strange/surprising, it is no wonder, it is necessary(important)等结构后的主语从句中常采用虚拟语气形式(should+动词原形),表示遗憾、惊奇、重要等作用,should 有时可省略。如:
It is a great pity that he should be so greedy.真遗憾,他竟然那么贪婪。
It is strange that he should have failed to see his own short comings.真奇怪,他竟没有看出自己的缺点。
(7)由 wh-系列引导词引导从句,也可以用 it作形式主语。如:
It doesn't matter too much whether he's coming or not.他来还是不来没有多大关系。
It is more time what we need.我们需要的是更多的时间。
It is still open to question who is to head the group谁领导这个小组还没定下来。
2.语序、主谓一致问题
主语从句的语序为陈述句语序。主语从句作主语,谓语动词一般用第三人称单数形式。如:
When they will start hasn't been decided.他们什么时候动身还未决定。
Howhe managed to finish this beautiful composition in such a short time is a mystery.他怎么在如此短的时间内写完这篇优美的作文是一个谜。
What was once regarded as impossible has come true.从前被认为不可能的事现在都实现了。
What we need is more money.我们所需要的是更多的钱。
3.强调结构和主语从句的区别
主语从句的句型指的是“It is + 形容词/名词 + that 从句”区别
①:含有主语从句的句子在译成汉语时不可加上“正是”或“就是”之类的字眼,而强调结构可以。
区别
②:含有主语从句的句子删掉“It is+that”,则原句在结构和意义上均不成立;而强调结构若去掉强调结构标志后,原句在结构和意义上仍然成立。
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