a few hours earlier和a few hours ago的区别
在新概念第二册的Lesson7里,有这么一段话,A few hours earlier,someone had told the police that thieves would try to steal the diamonds中A few hours earlier为什么不能用a few hours ago替换呢?这俩个短语有什么区别,分别用在什么情况下,最好能多举几个例子.