1) 同位语从句是对与之同位的名词中心词作进一步解释，能接名词性从句的常见名词有:

　　idea, fact, news, belief, hope, evidence, opinion, problem, truth, answer, proposal, theory, decision, discovery, problem, thought, understanding 等。

　　The news that he has passed the examination is exciting.

　　2) 同位语从句与定语从句的区别在于：定语从句是对先行词加以修饰、限制，而同位语从句时说明名词中心词的具体内容;that在定语从句中充当成分，为关系代词，而在同位语从句中不做任何成分,仅起连词作用。如：

　　The fact that we talked about is very important. (定语从句)

　　The fact that he succeeded in the experiment pleased everybody.( 同位语从句)