1、1名词性从句精讲来源：普特英语在复合句中起名词作用的从句叫名词性从句，包括作主语从句、表语从句、宾语从句和同位语从句。(1)主语从句就是在复合句中作主语的从句。主语从句常用 that, whether, who, whom, whose, what, which, when, where, how, why, whatever, whoever 等引导。如：Whether he will be able to come remains a question. 他是否来还是问题。That China is a great socialist country is well known. 众所周知
2、，中国是一个伟大的社会主义国家。注：为避免头重脚轻，使句子平衡，常用 it 作形式主语，而将主语从句后置。如上述第二例常说成：It is well known that China is a great socialist country.但是，由连接代词 what, whatever, whoever 等引导的主语从句一般不能用形式主语。如：What he found surprised me greatly. 他的发现使我非常吃惊。Whoever is finished may rest. 凡是做完工的人都可以休息。(2)表语从句就是在连系动词之后作表语的从句。引导表语从句的连接除与引导主
3、语从句的连接词外，还有 as if， as though。如：The question is whether he is able to do it alone. 问题是他能否单独做这件事。It looks as if (though) it is going to snow. 天好像要下雪似的。注意：要区分以下句式：1. thats why+结果；thats because+原因。2. the reason why /foris thatHe is absent. Thats because he is ill. 他缺席，这是因为他生病了。He is ill. Thats why he is
4、 absent. 他病了，这就是他缺席的原因。The reason why he is absent is that he is ill. 他缺席的原因是他生病了。(3)宾语从句就是在复合句中作宾语的从句。引导这宾语从句的连接词与引导主语从句的连接词基本相同。如：They didnt say which they wanted. 他们没有说他们想要哪一个。I am sure (that) no harm will ever come to you. 我肯定你永远不会受伤害。I was surprised at what has happened.我对发生的事感到惊讶。注意：当 think, b
5、elieve, suppose 等的疑问式后面跟连接代词或连接副词引导的宾语从句时，习惯上将这些连接词置于句首，即“连接代/副词do you think /believe /expect宾语从句2的其余部分？”如：Who do you think is the best player this year? 你认为今年谁是最佳运动员?What do you suppose you will do after school? 你想放学后干什么？(4)同位语从句就是在句中作同位语的从句。它通常有放在 thought, idea, news, word(=news), plan, doubt, que
6、stion, fact, suggestion, belief 等抽象名词的后面，说明这些词的具体内容或含义。同位语从句大多由 that 引导，也可由 whether, how, when, where, why 等引导，但不能由which 引导。如：The idea that the earth is round is not a new one. “地球是圆的”这种观点并不新鲜。He must answer the question whether he agrees to it or not. 他必须回答他是否同意此事这们一问题。I have no idea when he will s
7、et out. 我不知他什么时候出发。注：有时，同位语从句并不紧跟在它所说明的词的后面。如：The whole truth came out at last that he was a wolf in sheeps clothing. 真相终于大白了，他原来是一只披羊皮的狼。注意 1 语序问题不管什么词引导，从句的语序始终用陈述语序。如：(1)He asked how he could find his courage. 他问道他如何才能找到他的勇气。(2)The question is why there is little rain here. 问题是这里为什么雨水少。注意 2 连接词的选
8、用问题Athat，whether，if，as if(限用于表语从句)都不作句子的任何成分。因此，它们所引导的句子结构必须完整。that 一般用于确定的语气中，引导宾语从句时，口语中的 that 可省略，而其他情况中的 that 一般不可省；而 whether，if 一般用于不确定的语句中。如：(1)That he learnt English before is certain. 他学过英语是肯定的。(2)I dont know whether / if he will come. 我不知道他是否会来。(3)He looks as if he knows the answer. 看起来他好像知
9、道答案。Bwhether 和 if1)whether 可用于任何名词性从句中，而一般只能用于宾语从句中。如果 if 引导主语从句时，只能放在句中，而不能置于句首。如：(1)Whether he will come or not doesnt matter. It doesnt matter whether he will come or not. 他来还是不来都没关系。(2)Do you know if / whether his words are true. 你知道他的话是否真实吗？32)whether 可与 or not 连用，而 if 则不可以。如(1)Im not sure whet
10、her / if he can overcome the difficulties. 我没有把握他能否克服这些困难。(2)The radio didnt say whether it would rain or not tomorrow. 收音机并没有报道明天是否下雨。3)若用 if 会产生歧义时，则用 whether。(1)Let me know whether he will come. 告诉我他是否会来。(2)Let me know if he will come. 可理解为：告诉我他是否会来。也可理解为：如果他愿意来，就告诉我一声。4)whether 可与不定式连用，而 if 不可以。
11、Have you decided whether to go there tomorrow? 明天是否去那儿，你决定了吗？(句子中的whether 不能用 if 替换)5)whether 引导的从句可作某些介词及动词 discuss 的宾语，而 if 则不可以。如：(1)They are talking about whether they will take part in the strike. 他们在谈论他们是否要参加这次罢工。(2)They are discussing whether they can employ the new way. 他们在讨论他们是否可以采用这种新的方法。(
12、以上两个句子中的 whether 不能用 if 替换)6)宾语从句若为否定句，连接词则用 if 而不用 whether。如：Do you know if he hasnt been to Washington? 你知道他是否没有去过华盛顿吗？此句子中的 If 不能用 whether 替换。一、词序问题名词性从句总是用陈述句词序，则不能使用疑问句词序，尤其是当名词性从句由“疑问词”引导时，不能受疑问句的影响而误用疑问句词序：误：I didnt know where did he live.正：I didnt know where he lived. 我不知道他住哪儿。误：Who will he
13、marry remains unknown.正：Who he will marry remains unknown. 他同谁结婚还不知道。二、时态问题由于由 when 引导的时间状语从句和以 if 引导的条件状语从句要用现在时表示将来意义，而不能直接使用将来时态，所以许多同学容易受此影响在 when 和 if 引导名词性从句时也用现在时表示将来意义。请看几题：(1) I dont know if he _ or not tomorrow.A. come B. comesC. will come D. is coming此题答案选 C，句中 if 引导的不是条件状语从句 (if如果)，而是宾语从
14、句(if是否) ，句4意为“我不知道明天他是否会来。 ”(2) I dont know if she _, but if she _ I will let you know.A. comes, comes B. will come, will comeC. comes, will come D. will come, comes答案选 D，第一个 if 引导的是宾语从句，第二个 if 引导的是条件状语从句。(3) “When he _ is not known yet.” “But when he _, he will be warmly welcomed.”A. comes, comes B
15、. will come, will comeC. comes, will come D. will come, comes答案选 D，第一个 when 引导的是主语从句，第二个 when 引导的是时间状语从句。另外，当主句为过去时态时，宾语从句通常要用过去的某种时态与之呼应(表客观真理时除外)：The teacher told us that he knew everything. 老师告诉我们他知道一切。The teacher told us that light travels faster than sound. 老师告诉我们光比声音传播得快。一、什么叫同位语当两个指同一人或事物的句子成
16、分放在同等位置时，若其中一个句子成分是用于说明或解释另一个句子成分的，那么用于起说明或解释作用的句子成分就叫做另一成分的同位语。如：Laura Myers, a BBC reporter, asked for an interview. 劳拉 迈尔，BBC 的记者，要求采访。Influenza, a common disease, has no cure. 流行性感冒是一种常见病，无特效药。Mary, one of the most intelligent girls I know, is planning to attend the university. 玛丽是我所认识的最聪敏的姑娘之一，
17、她正准备上大学。Who is that man, the first in the front row? 前排第一个人是谁?We have two children, a boy and a girl. 我们有两个孩子，一个男孩和一个女孩。以上所举的同位语例子都是同位语的基本形式，一般不会出错。但有有几种同位语，或由于身本结构特殊，或由于它修饰的成分结构比较特殊，往往会引起误解。现小结并举例说明如下，希望引起同学们的注意。二、特殊同位语归纳1. 代词 we, us, you 等后接同位语Are you two reading? 你们二人在看书吗 ?They three joined the s
18、chool team. 他们 3 人参加了校队。She has great concern for us students. 她对我们学生很关心。He asked you boys to be quiet. 他要你们男孩子安静些。We girls often go to the movies together. 我们女孩子经常一起去看电影。2. 不定式用作同位语Soon came the order to start the general attack. 很快下达了发起总攻的命令。 (to start the general attack 与 the order 同位)He followed
19、 the instruction to walk along a certain street where I picked him up. 他照吩咐沿某一条街走，我在那里接他上了车。(to walk along 与 the instruction 同位)3. -ing 分词用作同位语5Hes getting a job tonight driving a truck. 他今晚得到一个开卡车的差事。(driving a track 与a job 同位)She got a place in a laundry ironing shirts. 她在一家洗衣店得到一个熨衣服的职位。(ironing
20、shirts 与 a place 同位)The first plan, attacking at night, was turned down. 第一个计划是夜袭，被拒绝了。(attacking at night 与 the first plan 同位)4. 形容词用作同位语The current affair, the biggest in its history, is being held in Guangzhou. 目前的交易会，是有史以来规模最大的，正在广州举行。He read all kinds of books, ancient and modern, Chinese and f
21、oreign. 他读了很多书，古今中外都有。People, old and young, took to the streets to watch the parade. 老老少少的人都来到街头观看游行。【注】这类同位语与定语比较接近，可转换成定语从句。如：The current affair, the biggest in its history, is being held in Guangzhou.=The current affair, which is the biggest in its history, is being held in Guangzhou.当名词后面所接的从句表
22、示与名词同位并为名词的实际内容时，这个从句就是同位语从句。如：The news that China has joined the WTO excite us all. 中国加入了世界贸易组织这一消息使我们大家兴奋不已。He told us the truth that he fell down from his bike this afternoon. 他告诉了我们他从单车上摔下来这一真相。同位语中应注意：1. 高中所学能带同位语从句的名词不多，常见的有：answer, belief, conclusion, decision, discovery, doubt, explanation,
23、fact, hope, idea, information, knowledge, law, message, news, opinion, order, possibility, problem, promise, proof, proposal, question, report, risk, rumor, story, suggestion, truth, theory, thought, wish, word 等。如：Hw sent us a message that he wont come next week. 他送信来告诉我们说，下周他不来了。There is no doubt
24、that he is fit for this job. 毫无疑问，它适合这一工作。2. 表示 “命令、建议、要求” advice, demand, decision, desire, idea, insistence, instruction, order, plan, proposal, recommendation, request, requirement, suggestion, wish 等名词的同位语，须用虚拟语气。如：He made clear his desire that he should work hard to go to college. 他已清楚的表明了他要努力学
25、习考上大学这一愿望。Soon came the order that all the people should obey the rules. 不久命令下来了，所有的人不得违犯制度。3. 同位语从句与定语从句的区别：同位语从句与定语从句形相似而实质不同，具体表现在以下几个方面：6(1)被修饰的词不同。同位语从句的前面一般是数量有限的、表示抽象意义的名词；而定语从句的先行词是无数的指人或物名词。(2)从聚的作用不同。同位语从句表示同位名词的具体内容；而定语从句是对先行词名词的限制、描绘或说明。(3)引导词的作用不同。引导同位语从句的 that 是连词，在从句中不担任任何成分，但不能省略；而引导
26、定语从句的 that 为关系代词，在从句中担任句子的某种成分，当担任定语从句中的宾语时，that 可以省略。(4)引导词不同。定语从句不能用 what, how, whether 引导；而同位从句可以用 what, how, whether 引导。(5)判定定语从句和同位语从句的方法。同位语从句可充当同位名词的表语；而定语从句不能充当先行词的表语。同位语从句的引导词：引导同位语从句的词语通常有连词 that，whether，连接代词和连接副词等。1. 由 that 引导We heard the news that our team had won. 我们听到消息说我们队赢了。They were
27、 worried over the fact that you were sick. 他们为你生病发愁。The news that we are having a holiday tomorrow is not true. 明天放假的消息不实。Ive come to the conclusion that it was unwise to do that. 我得出结论这样做是不明智的。The fact that the money has gone does not mean it was stolen. 那笔钱不见了这一事实并不意味着是被偷了。He referred to Copernicu
28、s statement that the earth moves round the sun. 他提到了哥白尼关于地球绕太阳转的说法。【注意 1】在某些名词(如 demand, wish, suggestion, resolution 等)后面的同位语从句要用虚拟语气。如：They were faced with the demand that this tax be abolished. 他们面对废除这个税的要求。They expressed the wish that she accept the award. 他们表示希望她接受这笔奖金。There was a suggestion th
29、at Brown should be dropped from the team. 有一项建议是布朗应该离队。The suggestion that the new rule be adopted came from the chairman. 采纳新规则的建议是主席提出的。The resolution that women be allowed to join the society was carried. 允许妇女参加这个协会的决议通过了。I can understand their eagerness that you should be the main speaker. 我理解他们
30、希望你作主要发言人的殷切心情。【注意 2】引导同位语从句的连词 that 通常不省略，但在非正式文体中也可以省去。如：He gabbed his suitcase and gave the impression he was boarding the Tokyo plane. 他拿起了手提箱，给人的印象是他要登上飞往东京的飞机了。2. 由 whether 引导There is some doubt whether he will come. 他是否会来还不一定。7Answer my question whether you are coming. 你回答我的问题：你来不来。The questi
31、on whether it is right or wrong depends on the result. 这个是对还是错要看结果。We are not investigating the question whether he is trustworthy. 我们不是在调查他是否可以信任的问题。【注意】whether 可引导同位语从句，但 if 不能引导同位语从句。3. 由连接代词引导Have you any idea what time it starts? 你知道什么时候开始吗 ?From 1985-90 I was an instructor at the regional part
32、y headquarters. After that I went back to work in a factory. Then I had no idea what a casino was. 从 1985 年到 1990 年我是地方党部的教员。随后我回到一家工厂工作。当时我不知道赌场是什么样的地方。4. 由连接副词引导I have no idea when he will come back. 我不知道他什么时候回来。It is a question how he did it. 那是一个他如何做的问题。He had no idea why she left. 他不知道她为什么离开。You have no idea how worried I was! 你不知道我多着急!
