你好, 同位语从句和定语从句最大的区别就是同位语从句只是起连接的作用,在从句中不充当任何成分,同位语从句的连接词较多的是用that连接;定语从句的关系代词、关系副词则在从句中会充当一定的成分。 如:He draws the conlcusion that she will not come.(that引导同位语从句) He told us a story which / that was about the ghost.(which 在定语从句中作主语) He knows the truth that every one is equal in front of the law.(that 引导同位语从句) It was the day when I first met him.(when在定语从句中作时间状语)
定语从句却缺成分,同位语从句不缺;同位语从句与先行词同位或等同,定语从句则与先行词是修饰关系。 I don't know the reason (why he was so angry).中的定语从句缺少原因状语。 I can't believe the reason (he offered){ that he got a fever}.中定语从句中缺少宾语,而同位语从句是完整的。