he was reported to have covered 30 miles on foot that day.为什么用have done?

题目

he was reported to have covered 30 miles on foot that day.为什么用have done?
既然是报道之前就走完了 那为什么不用过去完成时呢？

答案

因为在report之前,他走了30 miles,这里有个时间的先后顺序.在报道之前,他就已经做了某件事,所以用了完成时.译：据报道,那天他步行走了30公里.也可以改成下面的,或许会更好理解.It was reported that he had covered ...