【问】 (a) The news that we are having a holiday tomorrow is not true.
 (b) The news that appeared in the papers this morning was well received.
 上面两句中的that从句是否都是同位语从句?我在教学中发现，区分同位语从句与定语从句有时候是困难的。请讲一讲如何区分它们。
 【答】 在一般情况下，同位语从句与定语从句的区别是很明显的，如果掌握住它们的如下几个特征，并不难区分。
 A.从意义上看：同位语从句所表达的内容与作为中心词的名词短语所表达的内容可以划上一个等号。例如：
 1. He heard the news that his team had won.
 (the news=his team had won)
 2. He came to the decision that he must act at once.
 (the decision=he must act at once)
 或者说，同位语从句可以变为中心词的表语从句：
 He came to the decision that he must act at once. (the decision was that he must act atonce. )
 而定语从句则是限制或修饰中心词的，中心词所表达的内容不能与定语从句所表达的内容划等号。例如句(b)中的the news≠that appeared in the papers this morning。定语从句也不能变为中心词的表语从句：×The news was that appeared in the papers this morning.B.从that从句中that的语法功能上看：在同位语从句中，that只是一个连词，不充当从句的任何成分，而在定语从句中，that则必定充当句子的一个成份(主语、宾语等等)。请对比：The fact that the prisoner was guilty was plain to everybody.(Eckersley)(that不充当句子的任何成分)
 这个犯人有罪这一事实是人人都看得清楚的。
 It is a question that needs very careful consideration.(Yeats) (that充当从句的主语)。
 这是一个需要认真考虑的问题。
 C.从充当中心词的名词特点上看：充当定语从句的中心词的名词是无限的，而充当同位语从句的中心词的名词只是有限的一些表示概括意义的抽象名词：assumption(假设)，fact
 (事实)，idea(想法)，news(新闻) ，belief(信念)，message(信息)，proposal(建议)，proposition(建议)，evidence(证据)，proof(证据)，possibility(可能性)，suggestion(建议)等。
 1. I have a feeling that our team is going to win. (JED)
 我有一种感觉，我们的球队将取胜。
 2. We'll be there tomorrow on the assumption that it doesn't rain. (CGEL)
 假如明天不下雨的话，我们将去那里。
 3. The suggestion that the new rule be adopted came from the chairman. (CGEL)
 必须采用新规则的建议是主席提出来的。
 4. Obviously there was little probability that they would succeed，but they didn't mind.(PEG)
 很显然，他们成功的可能性极小，但是他们不在意。