sentry|sentries

城堡的高塔上站着一名警惕的哨兵。

A watchful ___sentry stood on the castle's high tower.

营地入口处有两名哨兵站岗。

There are two ___sentries posted at the entrance of the camp.

哨兵在基地入口处检查每个人的通行证。

The ___sentry checked everyone's pass at the base entrance.