【考例一】They have no idea at all________.

　　A. where he has gone B. where did he go

　　C. which place he has gone D. where has he gone

　　【解析】正确选项应为同位语从句(作idea的同位语)。由于名词性从句要用陈述语序，故先排除B、D两项。C项中的which place为名词短语，gone后边缺少介词to。故本题选A。

　　【要点】同位语从句是名词性从句的一种，在学习时应重点掌握以下几点：

　　1. 从句用陈述语序；

　　2. 一般情况下，主从句的时态应保持一致。但当从句表示的是客观事实或普遍真理时，从句仍然用一般现在时；

　　3. 表示“命令；要求；建议”的名词order, demand, suggestion等后接同位语从句时，从句的谓语要用虚拟语气，即 “(should)＋动词原形”。

　　【例句】 They were all very much worried over the fact that you were sick. 对于你生病这件事，他们都很着急。

　　Magellen's men's return from the voyage proved the truth that the earth is round. 麦哲伦的海员们的航海回归证实了地球是圆的这一真理。

　　They mainly discussed the suggestion that a big dam (should) be built there. 他们主要讨论了在那里建一个大坝这条建议。

　　【考例二】________is no possibility________Bob can win the first prize in the match.

　　A. There; that B. It; that

　　C. There; whether D. It; whether

　　【解析】There is no possibility that...意为“没有……的可能性”，其中that 引导同位语从句。故本题选A。

　　【要点】引导同位语从句的引导词常用that，此外还有whether, when, where, who, what, which, why, how等。选用引导词时，要结合整个句意来考虑。如：

　　【例句】The question who should do the work requires consideration. 谁该干这项工作这个问题需要考虑。

　　There is no doubt that he will come here again. 他会再来这里，这是无疑的。

　　He was tortured by the doubt whether he would accept their presents.他被是否接受他们的礼物这个疑虑折磨着。

　　【考例三】 Information has been put forward________more middle school graduates will be admitted into universities.

　　A. while B. that C. when D. as

　　【解析】纵观全句可知，information与同位语从句被谓语动词隔开。根据句意，应用that来引导。故本题选B。

　　【要点】有时为了避免头重脚轻，可以把同位语从句与名词分开。

　　【例句】 Word came that he had passed the final exam. 他已经通过期末考试的消息传来了。

　　【考例四】Is this the reason________at the meeting for his carelessness in his work？

　　A. he explained B. what he explained

　　C. how he explained D. why he explained

　　【解析】本题选A。he explained 为定语从句，省去了关系代词that或which。

　　【要点】同位语从句与定语从句的区别：

　　1. 从句的性质不同：同位语从句用来解释或说明名词的具体内容，二者之间是同位关系；定语从句用来说明先行词的性质或特征，起修饰或限制作用，二者之间是修饰与被修饰的关系。

　　【例句】We can't solve the problem how we can travel faster than light. 如何才能超过光的速度，我们解决不了这个问题。(how从句是the problem的具体内容，为同位语从句)

　　I can't remember the problem that they have. 我记不得他们的问题了。(problem就是have的对象，至于the problem的具体内容，没有说明，故是定语从句)

　　2. 引导词的作用不同：同位语从句的引导词不充当句子成分；定语从句的引导词充当句子成分并指代前面的先行词；同位语从句的引导词that 一般不可省略。

　　【例句】 Jim got to know the news that the whole village was in great danger. 吉姆得知整个村子都处在极度危险中的消息。(同位语从句)

　　I have no idea when he will come back. 我不知道他什么时候回来。(同位语从句)

　　Do you know the news (that ／ which) Jim told me？(定语从句) 你知道吉姆告诉我的那个消息吗？

　　(文/张书红；英语辅导报初中教师版04~05学年第25期；版权归英语辅导报社所有，独家网络合作伙伴新浪教育，未经许可，不得以任何形式进行转载。)