该句型通常用于针对前面已经说明过的原因进行总结， 又如： That is why you see this old woman before you know, Jeanne. 珍妮， 这就是现在这个老太婆出现在你面前的原因。(前文提到Jeanne对老妇人显得苍老憔悴深感诧异， 说话人对她讲述了其中的原因之后，用这一句来进行概括)。// That is why I came. 这就是我来的原因。
下面是两个与―That is why...‖形式相似的结构， 它们与―That is why...‖结构之间的关系要能够辨析清楚：
(1)―That is why...‖与―That is the reason why...‖同义， 只不过从语法结构上讲， ―That is the reason why...‖中why引导的是—个定语从句， 将其中的the reason去掉则与―That is why...‖结构一样， 例如： That is (the reason) why I cannot agree. 这就是我不能同意的理由。
(2)―That is because...‖句型中从属连词because引导的名词性从句在此作表语， 这也是个常用句型， 意为―这就是为什么……/因为……‖。―That is because...‖与―That is why...‖之间的不同在于―That is because...‖指原因或理由， ―That is why...‖则指由于各种原因所造成的后果， 例如： He did not see the film last night. That is because he had to help his little sister with her homework.昨天晚上他没有去看电影， 那是因为他得帮助他的妹妹做作业。(第一句话说明结果， 第二句话说明原因)
He had seen the film before. That is why he did not see it last night.他以前曾看过那部电影， 因此他昨天晚上没有去看。(第一句话说明原因， 第二句话说明结果)
五、同位语从句
1、同位语从句说明其前面的名词的具体内容。同位语从句通常由that引导，可用于同位语从句的名词有advice、demand、doubt、fact、hope、idea、information、message、news、order、problem、promise、question、request、suggestion、truth、wish、word等。例如：
The news that we won the game is exciting. 我们赢得这场比赛的消息令人激动。 I have no idea when he will come back home. 我不知道他什么时候回来。 The thought came to him that Mary had probably fallen ill. 他想到可能玛丽生病了。
同位语从句和定语从句的区别：
that作为关系代词，可以引导定语从句，充当句子成分，在从句中作宾语时可以省略； that引导同位语从句时，起连词的作用，没有实际意义，不充当句子成分，一般不能省略。 试比较下面两个例句:
I had no idea that you were here．（that引导同位语从句，不能省略）
Have you got the idea（that）this book gives you of life in ancient Greece？（that引导定语从句，作宾语，可以省略）
2、简介
同位语部分是个句子,就是同位语从句,这种用法比较\固定\把关键的几个词背下来.
一、在复合句中用作同位语的从句叫同位语从句。它一般跟在某些名词后面，用以说明该名词表示的具体内容。如： I heard the news that our team had won．我听到了我们队获胜的消息。 I had no idea that you were here．我不知道你在这里。
二、可以跟同位语从句的名词通常有news，idea，fact，promise，question，doubt，thought，hope，message，suggestion，words（消息），possibility等。如：
I’ve come from Mr wang with a message that he won’t be able to see you this afternoon． 我从王先生那里来，他让我告诉你他今天下午不能来看你了。
三、英语中引导同位语从句的词通有连词 that，whether，连接副词 how,when,where等。（注：if,which 不能引导同位语从句。）如：
l have no idea when he will be back．我不知道他什么时候回来。
He must answer the question whether he agrees to it or not. 他必须回答他是否同意这样一个问题。
- 37 -
四、有时同位语从句可以不紧跟在说明的名词后面，而被别的词隔开。 如： Several years later，word came that Napoleon himself was coming to inspect them． 几年以后，有消息传来说拿破仑要亲自视 察他们。
The thought came to him that maybe the enemy had fled the city． 他突然想起可能敌人已经逃出城了。 六、名词性that-从句
1）由从属连词that引导的从句叫做名词性that-从句。 That只起连接主句和从句的作用，在从句中不担任任何成分，本身也没有词义。名词性that-从句在句中能充当主 语、宾语、表语、同位语和形容词宾语，例如： 主语：That she is still alive is her luck. 他还活着全靠运气。
宾语：John said that he was leaving for London on Wednesday. 约翰说他星期三要到伦敦去。 表语：The fact is that he has not been seen recently. 事实是近来谁也没有见过他。 同位语：The fact that he has not been seen recently disturbs everyone in his office. 近来谁也没有见过他，这一事实令办公室所有的人不安。
形容词宾语：I am glad that you are satisfied with your job.你对工作满意我感到很高兴。
2）That-从句作主语通常用it作先行词，而将that-从句置于句末，例如：
It is quite clear that the whole project is doomed to failure. 很清楚，整个计划注定要失败。 It's a pity that you should have to leave. 你非走不可真是件憾事。 用it作形式主语的that-从句有以下四种不同的搭配关系： a. It + be +形容词+ that-从句
It is necessary that… 有必要…… It is important that… 重要的是…… It is obvious that… 很明显…… b. It + be + -ed 分词+ that-从句
It is believed that… 人们相信…… It is known to all that… 众所周知…… It has been decided that… 已决定…… c. It + be +名词+ that-从句
It is common knowledge that… ……是常识 It is a surprise that… 令人惊奇的是…… It is a fact that… 事实是…… d. It +不及物动词+ that-从句
It appears that… 似乎…… It happens that… 碰巧…… It occurred to me that… 我突然想起……
七、名词性wh-从句
1）由wh-词引导的名词从句叫做名词性wh-从句。Wh-词包括who, whom,. whose, whoever, what, whatever, which, whichever等连接代词和where, when, how, why等连接副词。Wh-从句的语法功能除了和that-从句一样外，还可充当介词宾语、宾语补语和间接宾语等，例如：
主语： How the book will sell depends on its author. 书销售如何取决于作者本人。 直接宾语：In one's own home one can do what one likes. 在自己家里可以随心所欲。 间接宾语：The club will give whoever wins a prize. 俱乐部将给得胜者设奖。
表语： My question is who will take over president of the Foundation. 我的问题是谁将接任该基金会主席职位。 宾语补足语：She will name him whatever she wants to. 她高兴给他起什么名字就取什么名字。 同位语： I have no idea when he will return. 我不知道他什么时候回来。
形容词宾语：I'm not sure why she refused their invitation. 我尚不能肯定她为什么拒绝他们的邀请。 介词宾语： That depends on where we shall go. 那取决于我们去哪儿。
2）Wh-从句作主语也常用先行词it做形式主语，而将wh-从句置于句末，例如： It is not yet decided who will do that job. 还没决定谁做这项工作。
It remains unknown when they are going to get married. 他们何时结婚依然不明。
- 38 -
八、if, whether引导的名词从句 1）yes-no型疑问从句
从属连词if, whether引导的名词从句是由一般疑问句或选择疑问转化而来的，因此也分别被称为yes-no型疑问句从句和选择型疑问从句，其功能和wh-从句的功能相同， 例如：
主语：Whether the plan is feasible remains to be proved. 这一计划是否可行还有等证实。
宾语：Let us know whether / if you can finish the article before Friday. 请让我们知道你是否能在星期五以前把文章写完。 表语：The point is whether we should lend him the money. 问题在于我们是否应该借钱给他。
同位语：They are investigating the question whether the man is trustworthy. 他们调查他是否值得信赖。 形容词宾语： She's doubtful whether we shall be able to come. 她怀疑我们是否能够前来。
介词宾语： I worry about whether he can pass through the crisis of his illness. 我担心他是否能度过疾病的危险期。
2）选择性疑问从句
选择性疑问从句由关联词if/whether…or或whether…or not构成，例如：
Please tell me whether / if they are Swedish or Danish. 请告诉我他们是瑞典人还是丹麦人。 I don't care whether you like the plan or not.我不在乎你是否喜欢该计划。
if和whether的区别：
1、 在动词不定式之前只能用whether 。如：
例8 I can’t decide whether to stay. 我不能决定是否留下。 2、 在whether …… or not 的固定搭配中。如：
例9 I want to know whether it’s good news or not . 我想知道是否是好消息。 3 、在介词后，只能用whether。如：
例10 His father is worried about whether he lose his work . 他的父亲担心是否会失去工作。 4、宾语从句放在句首表示强调时，只能用whether 。如： Whether this is true or not, I really don’t know. 这是否真的，我真的不知道。
（例11 Whether they can finish the work on time is still a problem . 他们是否能准时完成这项工作还是个问题。－－此例为主语从句，有误，感谢指出）
5、用if会引起歧义时，只用whether。如： 例12 Could you tell me if you know the answer ?
这句话有两种意思：―你能告诉我是否知道答案吗？‖或―如果你知道答案，请告诉我，好吗？‖。如用whether可避免歧义.
九、否定转移
1) 将think, believe, suppose, expect, fancy, imagine等动词后面宾语从句的否定词转移到主句中，即主句的谓语动词用否定式，而从句的谓语动词用肯定式。
I don't think I know you. 我想我并不认识你。 I don' t believe he will come. 我相信他不回来。
注意：若谓语动词为hope,宾语从句中的否定词不能转移。 I hope you weren't ill. 我想你没有生病吧。
2) 将seem, appear 等后的从句的否定转移到前面。
It doesn't seem that they know where to go. 看来他们不知道往哪去。
It doesn't appear that we'll have a sunny day tomorrow. 看来我们明天不会碰上好天气。 3) 有时将动名词，介词短语或整个从句的否定转变为对谓语动词的否定。 I don't remember having ever seen such a man.
我记得从未见过这样一个人。 (not否定动名词短语 having…)
It's not a place where anyone would expect to see strange characters on the street.
- 39 -
在这里，人们不会想到在街上会碰上陌生的人。 (anyone 作主语，从句中的谓语动词不能用否定形式。) 4) 有时状语或状语从句中否定可以转移到谓语动词前。
The ant is not gathering this for itself alone. (否定状语) 蚂蚁不只是为自己采食。
He was not ready to believe something just because Aristotle said so. (否定because状语) 他并不因亚里斯多德说过如何如何，就轻信此事。
She had not been married many weeks when that man's younger brother saw her and was struck by her beauty. (否定状语many weeks) 她结婚还不到几个月，这个人的弟弟就看见她了，并对她的美貌着了迷。
十、高考热点透视
1. ___ is a fact that English is being accepted as an international language. (NMET 1995) A. There B. This C. That D. It
答案D。当名词从句在句中作主语时，为避免句子头重脚轻，常用it作形式主语置于句首，而将真正的主语从句放在句尾。此时it只起先行引导作用，本身无实义。此句也可以改写为：That English is being accepted as an international language is a fact.
2．A computer can only do ____ you have instructed it to do．（NMET2001） A．how B．after C．what D．when
答案C。从句子结构可知，句子的空白处应该填引导宾语从句的连词，做主句谓语动词do的宾语，同时该连接词还是从句中的do的宾语，因此，此处的连接词应该用what。 3. He asked ____ for a violin．（MET1992）
A. did I pay how much B. I paid how much C. how much did I pay D. how much I paid 答案：D。宾语从句相当于特殊疑问句，句子语序要用陈述语序。
4. What the doctors really doubt is ____ my mother will recover from the serious disease soon．（上海2001年春季招生） A. when B. how C. whether D. why
答案C。这是一个表语从句。根据 doubt一词可知，所怀疑的应是是否能治好病，所以要填whether。这句话的意思是―医生真的怀疑我妈妈是否能很快从重病中恢复过来。‖ 5．It is generally considered unwise to give a child _____he or she wants. (NMET1997) A. however B. whatever C. whichever D. whenever 答案B。根据句意―一般认为孩子要什么就给什么是不好的。‖可以看出后面的从句应是一个宾语从句，而从句中wants缺少宾语，A. however 和D. whenever是不能作宾语的；排除A和D，whichever表示―无论哪一个，无论哪些‖，应表示一定范围内的人或物，此处没有涉及事物的范围，所以应选 B．whatever，表示―无论什么‖。 6. ______leaves the room last ought to turn off the lights. (MET1988) A. Anyone B. The person C. Whoever D. Who 答案C。本题句子的意思是：无论谁最后离开房间一定要把灯关掉。本题考查连接代词whoever引导的名词性从句，连接代词whoever可以引导名词性从句，并在从句中作主语，相当于any person who或The person who, 意为―一切……的人‖。而anyone和the person均非连词，不能引导从句，况who leaves the room last意为―某个最后离开房间的人‖，与题意不符，如果要选A. Anyone或B. The person，都必须在它们后面再加上引导定语从句的关系代词who。如果要选D. Who就体现不出―无论谁‖的含义了。
7. Sarah hopes to become a friend of ______shares her interests. (Shanghai1995) A. anyone B. whomever C. whoever D. no matter who
答案为C。本题句子的意思是：Sarah希望跟自己有共同爱好的人交朋友。疑问词+ever引导的名词性从句与no matter+疑问词引导的从句的区别是：前者既可以引导名词性从句也可以引导让步状语从句；后者只能引导让步状语从句。首先排除A和D，从句中需要的是主语，所以whomever也不行。 8. ---- I drove to Zhuhai for the air show last week.
---- Is that ______ you had a few days off ? ( NMET1999) A. why B. what C. when D. where
答案A。根据语境，甲说上周驱车去珠海观看航模展览。乙据此来询问甲这是否是请几天假的原因，故答案是A。答
- 40 -
