如何区分同位语从句和定于从句?

如何区分同位语从句和定于从句?
说说区别

一、 定语从句相当于一个形容词,它对先行词起修饰、描述和限制的作用.同位语从句相当于名词,属于名词性从句,它是对前面名词内容的具体表述,它们之间的关系是同位关系.试比较：
The news that you heard is not true.你听到的那个消息不是真的.（定语从句）
The news that he has died is true.他已经去世的消息是真的.（同位语从句,说明了 news 的具体内容,即he has died）
二、 同位语从句常跟在 news,fact,promise,idea,word,message,hope,truth,answer,proposal,suggestion,order,information 等少数名词之后,而一般名词之后都可跟定语从句.如：
The suggestion that the new rule be adopted came from the chairman.采纳新规则的建议是主席提出的.
He didn\'t give the answer why he was late.他没回答他为什么迟到这个问题.（同位语从句）
Then rose a question where we should go.于是产生了一个问题：我们该到哪里去?（同位语从句）
三、that 在定语从句中充当某一成分,是关系代词; that 在同位语从句中不作任何成分,仅把主句与从句连接在一起,是从属连词.如：
The fact that just now you talked about interests me.你们刚才谈论的事情使我感兴趣.（定语从句）
The fact that he failed in the exam made his parents very angry.他考试没及格这个事实使他的父母很生气.（同位语从句）
四、when,where,why,how,who,whom,which 如果引导定语从句,它们分别指前面先行词所表示的时间、地点、原因、方式、人和物,否则引导的就是同位语从句.试比较：
I still remember the day when he was killed.我还记得他被害的那一天.(定语从句)
I have no idea when he was killed.我不知道他什么时候被害的.（同位语从句）
They didn\'t go to the town where they were born.他们没有去他们出生的小镇.(定语从句)
They didn\'t answer the question where they were born.他们没有回答他们在哪里出生这个问题.（同位语从句）
五、whether,what 可引导同位语从句,但通常不可引导定语从句.
We have no information whether he is alive.我们不知道他是否活着.（同位语从句）
The problem whether it is right or wrong has not been decided yet.是对还是错,这个问题还未得到解决.（同位语从句）
Next comes the question what step we should take.接着的问题是我们下一步该做什么.（同位语从句）