moats

The castle had a deep moat which emptied into the lake.

城堡有一条很深的流入湖里的护城。

Consisting of concentric circles of stone surrounded by a moat (called a "henge"), Stonehenge was constructed in several stages over thousands of years.

石壕沟包围几圈巨大的同石块组成，巨石阵的建造数千年时间。

The city is square, the fence is 12 meters or so high, build by laying bricks or stones of outside and total brick, build on the wall have crenel, there is moat outside the wall.

城为方形,墙高12米左右,外表全部砖砌,墙上筑有垛口,墙外有护城。