英 [əˈlɜːt] 美 [əˈlɜːrt]

用法：

alert是一个名词，表示戒、报的意思，也可以作动词，表示使觉或者发出报。

例句：

1. The police were on alert for any suspicious activity in the area.

对该地区的任何可疑活动保持惕。

2. The alarm system will automatically alert the security company if there is a break-in.

如果有人闯入，报会自动向保安公司发出报。

3. The doctor advised her to stay alert for any changes in her condition.

医生建议她保持觉，留意身体状况是否有变化。

4. The government issued an alert for potential flooding in low-lying areas.

发布了低洼地区可能发生洪水的预。

5. I'll set an alert on my phone to remind me of the meeting tomorrow.

我会在手机上设置提醒，提醒我明天的。

同义词及用法：

1. Vigilant (adj.) - 惕的、机敏的

The security guards are always vigilant, ready to respond to any potential threats.

2. Alarm (n.) - 报

The fire alarm went off and we had to evacuate the building immediately.

3. Watchful (adj.) - 惕的、留心的

Be watchful of your surroundings when walking alone at night.

4. Wakeful (adj.) - 觉的、不眠不休的

The mother stayed wakeful all night, taking care of her sick child.

5. Caution (n.) - 谨慎、小心

He gave a word of caution to his colleagues before they embarked on the dangerous mission.

编辑总结：

alert是一个常用的词汇，既可以作名词也可以作动词，表示戒、报或者使觉。在日常生活中，我们经常会遇到这个词，比如在火灾、地震等紧急情况下，我们会听到“alert”这个词。除了作为名词和动词外，alert还可以作形容词，表示敏捷的、机敏的。在英语写作和口语中，使用alert能够让句子更加生动有力。因此，在学习英语的过程中，掌握好alert这个词的用法非常重要。