The wall is part of a large retaining wall that Herod the Great had built in biblical times.
问题描述：
The wall is part of a large retaining wall that Herod the Great had built in biblical times.
请解释一下为什么用过去完成时,
答
retain 保留The wall is part of a large retaining wall这堵墙是一面保留下来了的巨大的墙体的一部分retain虽然加了ing,但从句意可以看出,它其实是过去了的动作.那么build就是在retain之前的动作了,是“过去的过去...