一、名词性从句重难点归纳分析
1、that和what都可以引导名词性从句，但that是连接词，本身无词义，仅起连接作用，不在从句中担任任何成份；what是连接代词，不仅引导名词性从句，而且在从句中充当一定的成份，如主语、宾语或表语。
例 That he stole a bike was true. 他偷了一部自行车是真的。
The important thing is what you do,
but not what you say. 重要的是你做什么，而不是说什么。
2、单个的主语从句作主语时，谓语动词用单数形式。如果是两个或两个以上的主语从句作主语，谓语动词则用复数形式。
例 Where and when he was born has not been found. 他出生在何时何地还不知道。　　When the person was murdered and why he was murdered are still unknown. 那个人何时被谋杀，为什么被谋杀尚不知道。
3、在名词性从句中一律用陈述句的语序，即使从句表达的是疑问含义。
例 The problem is what he has done to the little boy. 问题是他对那个小男孩做了些什么。
4、连接词that引导的主语从句放在句首时，that不能省略。但为避免头重脚轻，可以用it作为形式主语，而把主语从句放到后面。如果that引导的主语从句出现在疑问句中时，必须以it作形式主语而把主语从句后置。
例 Is it true that the scientist will give us a lecture next week? 那个科学家下个星期给我们作报告是真的吗？
5、宾语从句的谓语动词时态受主句谓语动词的影响，如果主句的谓语动词是一般现在时，从句中的谓语动词可以用各种时态；如果主句中的谓语动词用了一般过去时，则从句中的谓语动只能用过去时的某种形式，但如果从句表达的是客观真理或客观存在则不受此影响。
例 We believed that he had earned enough money to build a house.我们相信他已经挣够足够的钱来建造房屋。
6、与“命令、要求、建议”等相关的名词性从句中通常用虚拟语气，虚拟语气的构成是“should＋动词原形”或省去should，直接用动词原形。
例 She insisted that she not be sent to the countryside.她坚持不被派到农村去。
但是，如果suggest作“表明、暗示”讲，insist作“坚持说、坚持认为”讲，则其后的宾语从句中应该用陈述语气。
例 The smile on his face suggested that he had passed the examination. 他脸上的微笑表明他已经通过了考试。
7、同位语从句一般跟在某些表示抽象概念
的名词后（如news, idea, information, fact, hope, thought, belief等），用来说明名词所表示的具体内容，引导同位语从句的连接词通常有that, whether和连接副词when, where, why, how；连接代词who，what，whose，which通常不能引导同位语从句。

例 I have no idea when she will be back.我不知道他何时回来。
8、whether和if均可引导动词后的宾语从句，常可互换。但从句中有or not时或介词宾语从句中只能用whether连接。其他名词性从句，如主语从句、表语从句、同位语从句只用whether连接，不用if。
例 I don’t care about whether you have money or not. 我并不在意你是否有钱。
9、介词后的宾语从句一般不用which和if引导，要用whether和what。that也很少引导介词宾语从句，只在except, but, besides等之后才用。
例 I could say nothing but that I was angry.我无话可说，只是感到生气。
10、引导宾语从句的连接词that一般可以省略，但如果有二个或二个以上的宾语从句时，只有第一个that可以省略。　　例 He said (that) the text was very difficult and that we had to work hard at it.他说课文很难，我们必须努力学习。
11、当主句是I/ We think ( suppose, expect, believe, guess, imagine) 时，其后的宾语从句如果是否定形式，常把否定词not从从句中转移到主句中，成为否定的转移。
例 We don’t believe that he will win the game. 我们相信他不会赢得这场比赛。
12、如果宾语从句后还有宾语补足语，则必须用it作形式宾语，而将宾语从句后置，并且that不能省略。
例 He has made it clear that he will not give in. 他清楚地表明他不会屈服。
13、doubt用于肯定结构时，后面用whether/ if引导名词性从句；用于否定结构或疑问结构时，后面用that引导名词性从句。be sure 用于肯定句或疑问句时，后接that引导的名词性从句；用于否定句时，后接whether/ if引导的名词性从句。
例 We doubt whether/ if he can win the game.我们怀疑他是否能赢得这场比赛。　
14、连接代词whoever，whatever，whichever可引导名词性从句，相当于anyone who, anything that等。他们也可以引导让步状语从句，相当于no matter who/ what/ which。
例 Whoever breaks the law should be punished. 任何违法的人都要受到惩罚。
二、高考链接
1. It is pretty well understood ___ controls the flow of carbon dioxide in and out the atmosphere today. (2003上海)
A. that B. when
C. what D. how
2. --- I think it’s going to be a big problem.
--- Yes, it could be.
--- I wonder ___ we do about it.(2002上海春)
A. if    B. how   C. what    D. that
3. You should make it a rule to leave things ___ you can find them often. (1999NMET)
A. when    B. where   C. then    D. there
4. A computer can only do ____ you have instructed it to do. (2001NMET)
A. how   B. after   C. what   D. when

5. You are saying that everyone should be equal, and this is ___ I disagree. (2004 NMET)
A. why   B. where   C. what   D. how
6. I like ___ in the autumn when the weather is clear and bright. (2004 NMET)
A. this B. that
C. it D. one
7. The road is covered with snow. I can’t u
nderstand ___ they insist on going by motor-bike. (2004NMET)
A. Why B. whether
C. when D. how　　8. We can’t figure out ___ quite a number of insects, birds, and animals are dying out.(2004 北京)
A. that B. as
C. why D. when
9. After Yang Liwei succeeded circling the earth, ___ our astronauts to do is walk in space. (2004 上海)
A. where B. what
C. that D. how
10. A story goes ___ Elizabeth I of England liked nothing more than being surrounded by clever and qualified noblemen at court. (2004 上海)
A. when B. where
C. what D. that
Key 1-5 CCBCB 6-10 CACBD
三、强化练习　　1. He has given us a suggestion ____ we should buy a cottage in the country, with the money we have saved.
A. when B. where
C. what D. that　　2. After five hours’ drive, they reached ____ they thought was the place they’d been dreaming of.
A. that B. where
C. which D. what
3. It is no longer a question now ___ man can land on the moon.
A. that B. which C. whether   D. what
4. She is pleased with ____ you have given him and all that you have told him.
A. that B. what　　C. why D. which
5. Father made a promise ____ I passed the exam, he would buy me a bicycle.
A. that B. if   C. whether D. that if　　6. ____ surprised me most was that she didn’t even know ____ the difference between the two lies.
A. What, where B. What, what
C. That, where D. That, what
7. Sometimes we are asked ___ we think the likely result of an action will be.
A. that B. what　　C. which D. whether
8. Nobody knows ___ he mentioned that at the meeting.
A. that B. why　　C. what D. where
9. There is no doubt ____ my friend was not important to them all.
A. that   B. whether C. if   D. why
10. I have no idea ____ they will visit our school; we have got everything ready.