that引导的定语从句和
同位语从句的区别
1、性质不同
同位语从句是名词（精）性从句，是对一个名词加以（锐）补充说明，定语从句是形容词性的，对一个名词加以修饰限定。
The news（that）he told me is really encouraging.(定语从句)
The news that our team has won the game is really encouraging.(同位语从句)
2、句法功能不同
同位语从句的连接词不充当
句子成分，但不可省略；定语从句的
关系代词代替
先行词在句中充当成分，充当宾语时可省略。
The news that he told me is really encouraging.(that在定语从句中做宾语)
The news that our team has won the game is really encouraging.(that在同位语从句中不作成分，只起连接作用)
3、先行词不同
同位语从句所修饰的名词比较有限，通常是抽象名词，有一定的内涵。常见的有idea, situation thought, fact, evidence, belief, doubt, fear, hope, question, theory, suggestion, proposal, word, thought, truth, possibility, promise, order，news, order, ability等等。
定语从句所修饰的名词则非常广泛，可以是名词､代词､主句的一部分甚至整个句子｡