Every few hundred meters along the wall there are watch-towers, where soldiers used to keep watch.

沿那边墙壁地每上百米是城楼，兵士曩昔经常保存…

youdao

Every few hundred meters along the wall there are watch-towers, where soldiers used to keep watch.

沿那边墙壁地每上百米是城楼，兵士曩昔经常保存…

youdao