"Alert" 是一个英文单词，通常翻译为“警报”或“警告”。它描述了一个提醒或警告的状态或行为，通常用于提醒某人或某事物可能出现的危险或问题。

以下是三个英文例句：

The fire alarm went off, alerting the building's occupants to the danger.

（火警响了，提醒大楼里的人有危险。）

The police were alerted to the robbery and quickly arrived at the scene.

（警察接到了抢劫警报，迅速赶到现场。）

The doctor warned his patient to be on the alert for symptoms of the flu.

（医生警告他的病人要警惕流感的症状。）