n.卫兵；哨兵

No one was excluded from sentry duty. 人人都得站岗放哨。

Paul has just come off sentry. 保罗刚退哨。

The sentry had orders to shoot on sight. 哨兵奉命一发现有动静就立即开枪。

The sentry was praised for his alertness in his post. 哨兵因他站岗时的机警而被称赞。

People approaching the gate were challenged by the sentry. 向大门走去的人受到了哨兵的查问。