where同位语从句与定语从句的区别（同位语从句与定语从句的区别）

1、从句的作用不同：同位语从句用来进一步说明前面名词的内容；定语从句用来修饰、限定前面的名词。 e.g. The news that our team has won the final match is encouraging. （从句说明“消息”的内容：我们队取得了决赛胜利。） The news that you told us is really encouraging.（从句对“消息”加以限定：是你告诉我们的，而非来自其他渠道。但消息是何内容却不得而知。）

2、引导从句的关联词that的功能不同：that引导同位语从句时是一个纯连词，不充当任何成分；而引导定语从句的that是关系代词，既指代先行词又须在从句中充当成分。e.g.Dad made a promise that he would buy me CD player if I passed the English test. （that 不充当任何成分） Dad made a promise that excited all his children.（that指代promise，又在从句中充当主语。）

3、that引导同位语从句时是一个纯连词，故不能用which替换；而that引导定于从句时是代词，常可以和另一关系代词which替换。e.g. The fact that he is from Canada is new to me. （that不可换为which） The fact that surprised me is that he is not Chinese.（第一个that可换为which，第二个不行，因为它引导的是表语从句。）

4、引导同位语从句关连词，除that外，还可以根据句义使用任何其它疑问代词或副词；而定语从句不可用what, how, whether等引导。e.g. I had no idea at all what I should do next. There is no proof whether he was killed by others.