The doctor whom you are looking for is in the room. 你找的那位医生在房间里面?(定语从句)

His mother did all she could to help him with his study. 他妈妈尽她的最大努力帮助他的学习?(定语从句,代词all作先行词?)

2. 从性质上区别

定语从句是从句对其先行词的修饰或限制,属于形容词性从句的范畴;而同位语从句是从句对前面抽象名词的进一步的说明和解释,属于名词性从句的范畴?如:

The news that our team has won the game was true. 我们队赢了那场比赛的消息是真的?(同位语从句,补充说明news到底是一个什么消息?)

The news that he told me yesterday was true. 昨天他告诉我的那个消息是真的?(定语从句,news在从句中作told的宾语?)

I made a promise that if anyone set me free I would make him very rich. 我许诺如果谁让我自由,我就让他非常富有?(同位语从句,补充说明promise到底是一个什么诺言?)