王牌要点：通常由 that或疑问词导出。

　　1. How some mammals came to live in the sea is not know.(主语从句)

　　2. The attorney told his client that they had little chance of winning the case.(宾语从句)

　　3. The problem is what we'll do next.(表语从句)

　　4. We have no idea that he has come back.(同位语从句)

　　同位语(Appositive):

　　同位语是英语语法的重点内容，也是各类考试中的一个考点，同时，在写作中正确运用同位语可以使你的句型更加简洁得体。

　　《新概念英语》 第三册第一课有这样一个句子： When reports came into London zoo that a wild puma had been spotted forty-five miles south of London, they were not taken seriously.

　　(当伦敦动物园接到报告说，在伦敦以南45英里处发现一只美洲狮时，这些报告并没有受到重视。)

　　在这里，a wild puma had been spotted forty-five miles south of London就是同位语从句，它本来应该放在 “reports”后面，这里却被放在了谓语成分 came into London zoo的后面，目的是让句型显得更为稳重。

　　I.简单记忆：同位语从句，就是对某些名词做进一步的解释的句子。

　　I was greatly shocked when I heard the news that his father died yesterday.

　　(that 引导的句子解释了news的内容，注意：that不做任何成分)

　　We have to face the fact that the weather is unexpectedly bad.

　　(that 引导的句子解释了fact的内容)

　　II.联想记忆：

　　能接同位词从句的名词有：belief(信仰)，fact，idea，doubt，rumor(谣言)，evidence(证据)，conclusion(结论)，suggestion(建议)，problem，order，answer，discovery(发 现)explanation(解释)，principle(原则)，possibility(可能性)，truth，promise(承诺)，report(报告)，statement(声明)，knowledge(知识)，opinion(观点)，likelihood(可能性)

　　[大声朗读三遍，背下即可。]

　　III.王牌要点：

　　● 同位语一般由that引导，但也可以用关系代词which, who, what和关系副词when, where, why, how或 whether 引导。

　　There arouse the question whether we could win the game.

　　I have no idea howto explain it.

　　● 一些介词词组后面也能引导同位语从句。(非常经典之功能句式，可用于四六级和托福作文，不妨一试!)：

　　on the assumption(在……前提下)，

　　on the ground(由于……原因)，

　　on the condition that(在……条件下)，

　　with the exception(有……例外)

　　owing to the fact(由于……事实);

　　on the understanding(基于……理解);

　　The young lady promised to marry the old man on the condition that he bought her a villa.

　　那位年轻的女士答应嫁给那位老头，条件是他给她买一幢别墅。

　　IV.分隔式同位语从句

　　为了使句型平衡不至于头重脚轻，有时同位语从句可以放到句子的末尾，(读两遍此定义，然后看倒句：)

　　An idea came to him that he might write to her to ask more information about the matter.

　　I got information from my friend that there will be a marvelous American movie "Titanic".

　　V. 同位语从句与定语从句之区别

　　简单记忆：定语从句的引导词 that 或 which在句子中用作主语或宾语，而同位语从句的引导词that只起连接主句和从句之作用，不用作任何成分。

　　示例：I've got an answer that A is right. (同位语从句，that 不做成分)

　　I've got an answer that surprised me a lot.(定语从句，that做定语从句的主语)

　　VI.王牌重点：可以充当同位语的词组或短语。

　　1)名词短语。(使句型更为简洁)

　　Bill Clinton, the president of America, came to China to pay an official visit in 1998.

　　Lu Xun, one of the greatest essayists in China, played an overwhelmingly important role in Chinese literature history.

　　2)动名词词组亦可用作同位语：别忘了加逗号。(使句型更为流畅)

　　I'm crazy about the game, playing baseball.

　　Going to concert, that sounds a great idea.

　　3)不定式短语。(陌生只是掌握的开始)

　　The problem what to do next remains unsolved.

　　Her claim to have finished his work is nothing but a white lie.

　　4)形容词词组。(有逗号隔开)

　　All the workers, young or old, should be treated equally.

　　Young man, short or tall, should have the right to take the opportunity.

　　VII. 同位语的引导词。(重要!这是中高级写作中不可缺少的引导成分)

　　引导词用来表示同位语与它所说明的同位成分之间的关系：

　　1.namely, that it is, that is to say(也就是说), in other words(换句话说), or, for short 表示等同关系。

　　2.such as, say, so to speak(譬如说), including(包括), for instance(或 for example (e.g. / eg)，表示举例和列举关系。

　　3.especially, mostly, chiefly, or better, in particular, particularly表示突出重点，(在高难度阅读中表示后面的部分为更重要或更突出的部分，是出题的关键点。)

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