直接引语中的when were you born在间接引语中用什么时态

问题描述

例句如下：

The policeman asked the thief, “when were you born?”

The policeman asked the thief when he / she was born.

转为间接引语后为何不是when he / she had been born(变为过去完成时)？

老师答疑

黎老师：

以下内容摘自最新出版的《牛津英语用法指南》第三版278节，可以作为对你的问题的解答：

在间接引语中，说话人用的过去时常常用过去完成时来转述。

......

直接引语：I saw penny at the theatre a couple of days ago. 我几天前在戏院见到了彭尼。

间接引语：In his letter, he said he'd seen penny at the theatre a couple of days before . 他在信中说他几天前在戏院见到了彭尼。

然而，并不总是用过去完成时，尤其是在即使不把过去时变成用过去完成时，时间关系也已经清楚的情况下。

This man on TV said that dinosaurs were around for 250 million years. 电视上的这个人说恐龙生存了2亿5千万年。 (不能说：...that dinosaurs had been around ...)