同位语表示与之同位的名词(短语)的实际内容，对前面的名词(短语)加以补充说明或进一步解释。
　　例如：
　　The suggestion that we should develop the natural resources in the region has been discussed.
　　关于我们应该开发本地区资源的建议已经讨论过了。
　　同位语从句的连接词
　　1. 引导同位语从句的连接词最常见的是that。
　　2. 连接词when, where, why, whether, how 等也可引导同位语从句。
　　例如：
　　Have you any idea how fast sound travels? 你知道声音传播有多快吗？
　　This is some doubt whether he will come. 他是否会来还不一定呢。
　　He had no idea why she left. 他完全不明白她为什么会离开。
　　3. 同位语从句中常见的先行词
　　idea, situation thought, fact, evidence, belief, doubt, fear, hope, question, theory, news, order, 等等。
　　注意：同位语从句和定语从句的区别
　　1. 修饰的词不同。同位语从句前的先行词比较有限，且大部分都是抽象名词；定语从句的先行词可以是比较复杂的内容，可以即包括人又包括物。
　　2. 从句的作用不同。同位语从句是用来解释前面的名词的，而定语从句则是修饰的作用。
　　3. 关系词的作用不同。同位语从句中that 是连词，不充当任何成分，但是不能省略。而定语从句中that 是充当一定成分的，在某些情形下是可以省略的。
　　翻译示例：
　　Many people have stopped buying it, ______________（尽管一再保证这种产品是安全的）.
　　1. 介词短语作状语：所以前半部分作句子的状语
　　2. 尽管可以用一个介词短语，despite，后面应该接名词短语
　　3. 同位语从句：assurance后面接一个同位语从句对“保证”进行说明。
　　答案：despite repeated assurances that the product is safe
　　实战演练：
　　1. They received orders ___________ the work be done right away.
　　A. which B. that C. where D. when
　　2. The news ___________ he was kidnapped surprised us greatly.
　　A. when B. what C. why D. that
　　3. Information has been put forward _________ more middle school graduates will be admitted into universities.
　　A. while B. as C. when D. that
　　4. Three days later, word came ________our country had sent up another man-made satellite.
　　A. which B. when C. that D. where
　　5. Along with the letter was his promise __________ he would visit me this coming Christmas.
　　A. which B. that C. what D. whether
　　6. The reason __________the little actress has been such a success is __________she is both clever and hard-working.
　　A. why, why B. why, that C. that, because D. for, because
　　7. A warm thought suddenly came to me __________ I might use the pocket money to buy some flowers for my mother's birthday．
　　A. if B. when C. that D. which
　　8. There’s a feeling in me__________ is- not ever.
　　A. which we’ll never know what a UFO
　　B. of which we never know what a UFO
　　C. when we never know what a UFO
　　D. that we’ll never know what a UFO
　　9. I've come from the government with a message __________.
　　A. if the meeting will be held tomorrow
　　B. whether the meeting will be held tomorrow
　　C. that the meeting won't be held tomorrow
　　D. which the meeting won't be held tomorrow
　　10. The thought__________.
　　A. of which he failed in the exam worried him
　　B. which he failed in the exam worried him
　　C. what he might fail in the exam worried him.
　　D. that he might fail in the exam worried him.

　　答案及解析：
　　答案：1. B 2. D 3.D 4.C 5.B 6.B 7. C 8. D 9.C 10. D
　　【解析】
　　1. 同位语从句。that引导从句作orders的同位语，解释orders的具体内容。主句：They received orders. orders内容如下：The work be done right away.
　　2. 同位语从句。that引导从句作news的同位语，解释news的具体内容。主句：The news surprised us greatly. news的内容如下：He was kidnapped.
　　3. that引导从句作information的同位语，解释information的具体内容。主句：Information has been put forward. information的具体内容为：More middle school graduates will be admitted into universities.
　　4. that引导从句作word的同位语，解释word的具体内容。主句：Three days later, word came.
　　word的具体内容为：Our country had sent up another man-made satellite.
　　5. that引导从句作promise的同位语，解释promise的具体内容。主句：Along with the letter was his promise. promise的具体内容为：He would visit me this coming Christmas.
　　6. 此题为故意考查大家是否能辨别同位语从句与其他从句使用that的区别而设置。并不考查同位语从句。第一空为定语从句，why和that都可引导定语从句修饰the reason；第二空为表语从句，根据句意“……的理由是”只能选择that，如果because或why就意为“……是因为”句意不通，所以，答案为B。
　　7. that引导从句作a warm thought的同位语，解释a warm thought的具体内容。主句：A warm thought suddenly came to me. a warm thought的具体内容为：I might use the pocket money to buy some flowers for my mother's birthday．
　　8. 同位语从句that we’ll never know what a UFO is- not ever作a feeling 的同位语，解释a feeling 的具体内容。that连接同位语从句时，只起连接作用，不作从句的任何成分。
　　9. that引导从句作a message的同位语，解释a message的具体内容。a message的具体内容为：The meeting won't be held tomorrow.
　　10. that引导从句作thought的同位语，解释thought的具体内容。主句：The thought worried him. thought的具体内容为：He might fail in the exam.