名词性从句把充当主语、表语、宾语或同位语的从句分别称为主语从句、表语从句、宾语从句或同位语从句。
也就是说充当什么成分就叫什么从句。
判断下列句子是那种名词名词性从句：1.Whether he will come or not is unknown.( )=It is unknown whether he will come or not.( )2.I don’t know whether he will come or not.( )3.The question is whether he will come or not.( )4.The question whether he will come or not is not settled.( )5.Whoever wants the book may have it. 任何人要这书都可拿去。
( )6.I’ll do whatever I can to help him. 我们将尽我们所能来挽救他。
( )7.Buy whichever is cheapest. 买最便宜的。
( )一、主语从句(一)用适当的连接词填空1.__________ we must master English words as many as possible is very important.我们必须尽可能多的掌握英文单词，这是很重要的。
2.__________ was most important to her, she told me, was her family.她告诉我对她来说最重要的是她的家庭。
3.___________ we shall go or stay is uncertain.我们是去还是留还不一定。
4.____________will be sent abroad has not been decided.派谁去国外还没有决定。
5.____________you are going to do it remains a mystery.你要怎样做这件事还是个谜。
6.___________ was responsible for the accident hasn’t been investigated.还不清楚谁对这次事故负责任。
7.___________ he goes on Sunday is his own affair.他星期天到哪里去是他的事。
8.__________ is here gets a prize.不管谁来，都能得奖。
(二)从句作主语时，多数情况下由it 作形式主语，而把主语从句放在后面，尤其是谓语部分较短的情况下1.It is a pity (a shame, a fact, a wonder, no wonder, a common knowledge, )that从句……2.It is true(clear, well known, likely, obvious, important, right…..)that从句……3.It is said (reported, proved, believed, arranged, thought, expected, announced,hoped……)that从句……4.It appears (happens, seems, turns out) that从句…….5.It doesn’t matter (makes no difference) +连接代词连或者接副词引导主语从句2.________he was chosen monitor was unknown to all.3._________ he chose was unknown to all.4.__________ one he chose was unknown to all.5.___________ surprised me most was ______ he was chosen monitor.6.He wanted to see for himself ________ the problems were.7.The teacher asked _______ subject was the most difficult to learn.8._________ we will go camping depends on the weather.9.1)________he told us at the meeting was true.2)_______ he said at the meeting was true.3)________ he spoke at the meeting was true.4)________ he said nothing at the meeting was true.二、同位语从句同位语从句是对名词的内容给予具体、详细的说明。
常在后面接同位语从句的名词有fact, news, idea，truth, hope, suggestion, question, problem, doubt, fear, belief等同位语从句常用的引导词为that,有是也用when, where 等疑问词1)The news _________the United States was hit by terrorist attacks took the whole world by surprise. 美国受到恐怖主义分子袭击的消息令全世界吃惊2)The idea __________ you can do this work well without thinking is quite wrong.你认为不动脑筋就能做好这件工作的想法是完全错误的3)People used to hold the belief _________ the earth was the center of the universe.人们曾认为地球是宇宙的中心4)The difficulty lies in the fact ________ we are short of money.困难在于我们缺乏资金这个事实5)They have no idea at all ________ he has gone.他们一点儿也不知道他去哪儿了注意：请辨别是同位语从句还是定语从句:1)The idea that some peoples are superior to others is sheer nonsense._____________有些民族优越于其他民族这种想法简直荒谬。
2)The idea that he proposed at the meeting is sheer nonsense. __________________他在会议上提出的这个想法简直荒谬。
3)No one is happy with the fact that he found out. __________________没有人对他发现的事实感到高兴。
4)No one is happy with the fact that he will become their boss. __________________没有人对他将成为他们的老板这一事实感到高兴。
三、表语从句(表语从句还可由as if ,as though, because引导)1.That’s not what I want. 那不是我要的2.My opinion is that things will improve.我的意见是事情会好起来的3.The problem is who is to pay and when we can start.问题是谁来付帐、我们又何时开始4._____ surprised me was that he spoke English so well.使我感到吃惊的是他英语讲得那么好.5._________ I want to know is __________ we shall go and _________ she will join us.我想知道的是我们要去什么地方以及她是否加入我们6.That’s ________I have come.那就是我为什么来了.7.That is __________ we differ(don’t agree).这是我们的分歧所在。
8.He was late for the meeting. That is __________ his car broke down on the way.9.It looks ___________ it is going to snow.看起来天要下雪。
10.Air is to us ___________ water is to fish.空气对于我们犹如水之与鱼。
四、宾语从句在谓语动词、介词、动词不定式、分词、动名词之后都可以带有宾语从句。
某些形容词如sure, happy, glad，certain, pleased 等之后也可以带有宾语从句1.that 引导的宾语从句: that 没有意义，在口语或非正式文体中常省略I really feel she’s making a mistake. 我的确感到她正犯错误Hearing that his son was badly wounded, he hurried to the hospital to see him 2．whether/ifHe asked me if/whether I knew John. 他问我是否认识约翰Let me know whether you can come or not. 你能来还是不能来，告诉我一声3．在think, believe, suppose, expect 等动词的宾语从句中，否定不用在从句中，而是将think 等词变为否定形式I don’t think the film is interesting.我觉得这部电影没什么意思I don’t suppose we are going outing tomorrow. 我认为我们明天不会出去郊游4．用it 作形式宾语，而将宾语从句放在句尾,常跟这样的复合宾语的动词有：make, find, see, hear, feel, think, consider, regard, take….for granted等George made it clear that he opposed this project. 乔治已明确表示他反对这个项目。
