警备

例句：

1. 1. The soldiers were ordered to guard the border against intruders.
   士兵们被命令守卫边境，防止入侵者。
2. 2. The policeman stood guard at the entrance of the station.
   警察站在车站入口处进行警戒。
3. 3. The cat was guarding its food when a mouse approached.
   猫在守护它的猎物时，一只老鼠靠近了。