突然觉得这个题目其实可以不用想那么多(因为我翻了一下曼哈顿的书,发现其实没必要多一个概念:是否在同一时间轴上)。因为gmat偏好简洁,这里是描述客观事实,不需要强调时间的顺序,曼哈顿第五版chapter7 p109那里的例子说得很清楚
joe learned about an epoch in which dinosaurs had walked the earth (×)
joe learned about an epoch in which dinosaurs walked the earth. (√)
请问一下,过去完成时有一种用法是表示过去的一段持续的一段时间,比如:The band U2 was just one of many new groups on the rock music scene in the early 1980's, but less than 10 years later, U2 HAD fully eclipsed its early rivals in the pantheon pf popular music. 那在这题里面,为什么冰川持续的一段时间不能用过去完成时呢?