【高中同位语从句精讲及练习题x】在英语语法中，同位语从句是一个较为复杂但又非常重要的知识点。它不仅在高考中频繁出现，而且在实际语言运用中也具有重要意义。本文将对“同位语从句”进行详细讲解，并附上相关练习题，帮助同学们更好地掌握这一语法点。

一、什么是同位语从句？

同位语从句（Appositive Clause）是指一个从句用来解释或说明前面的名词内容，该名词通常表示一种抽象概念，如“idea”、“fact”、“news”、“question”等。同位语从句的作用类似于同位语，但它不是简单的名词或代词，而是一个完整的句子。

例如：

- The fact that he passed the exam surprised everyone.

这里的“that he passed the exam”就是“the fact”的同位语从句，进一步说明了“fact”的具体内容。

二、同位语从句的引导词

常见的引导词有：that, whether, if, what, how, when, where, why, who, whom, whose, which 等。其中，“that”是最常用的引导词，尤其在正式或书面语中使用较多。

注意：that 在同位语从句中不充当任何成分，只起连接作用，不能省略。

三、同位语从句与定语从句的区别

这是很多学生容易混淆的地方，下面做一个简单对比：

| 项目 | 同位语从句 | 定语从句 |

|------|-------------|-----------|

| 功能 | 解释名词内容 | 修饰名词 |

| 引导词 | that / whether / what 等 | that / which / who 等 |

| 是否可省略 | that 不能省略 | that 可以省略（指物时） |

| 例子 | The idea that we should go is great. | The idea that we discussed is great. |

在第一句中，“that we should go”是“idea”的同位语从句；而在第二句中，“that we discussed”是“idea”的定语从句，修饰“idea”。

四、常见结构与用法

1. 名词 + that 从句

- The news that he won the prize is true.

- The rumor that she was leaving spread quickly.

2. 疑问词引导的同位语从句

- The question how we can solve it remains unsolved.

- The problem why he didn’t come is unclear.

3. whether / if 引导的同位语从句

- The doubt whether he will come still lingers.

- The possibility if they will agree is low.

五、同位语从句的判断技巧

1. 看前面的名词是否为抽象名词，如：idea, fact, news, question, belief, hope, fear, promise, truth, suggestion 等。

2. 从句是否是对该名词的具体说明，而不是对其修饰。

3. 引导词是否可以被替换为“that”，如果可以，则可能是同位语从句。

六、练习题

一、选择题：

1. The fact ______ he failed the exam surprised his teacher.

A. which

B. that

C. what

D. whether

2. I have no idea ______ he left so early.

A. when

B. why

C. that

D. whether

3. The question ______ we should go there is still open.

A. that

B. if

C. whether

D. what

4. The idea ______ we can finish the work on time is encouraging.

A. that

B. which

C. what

D. how

5. The problem ______ the new policy will be introduced next month is still under discussion.

A. if

B. whether

C. that

D. what

二、填空题：

6. The news ______ he has been accepted into the university is exciting.

7. We are discussing the question ______ we should take the job or not.

8. The belief ______ we must work hard is deeply rooted in our culture.

9. The reason ______ he was late is unknown.

10. The truth ______ he was lying came out yesterday.

七、答案与解析

一、选择题答案：

1. B

2. B

3. C

4. A

5. C

二、填空题答案：

6. that

7. whether

8. that

9. why

10. that

通过以上讲解和练习，相信你对同位语从句已经有了更深入的理解。建议多做相关题目，巩固所学知识，提升语言表达能力。希望这篇内容能对你的学习有所帮助！