Between each pair of milecastles lay two towers.

两座城堡之间有两座塔。

In front of both was a deep ditch and at each mile, a gate was protected by a small guard post called a milecastle.

在这两个地方的前面都有一条深沟，每隔一英里，都有一个门，由一个被称为 “里堡” 的小哨所保护。

Between each pair of milecastles lay two towers.The stone wall was to be 15 Roman feet high and 10 Roman feet wide.

在每对 milecastles 之间有两座塔楼。 石墙高 15 罗马英尺， 宽 10 罗马英尺。