来自vigil,警醒，警觉，守夜。

1. He warned the public to be vigilant and report anything suspicious.

他警告公众要提高警惕，遇到任何可疑情况都要报告。

2. A pilot must remain vigilant at all times.

飞行员必须随时保持警惕。

3. He has to learn how to remain vigilant through these long nights.

他得学会如何在这漫长的黑夜里保持警觉.

4. The dog kept a vigilant guard over the house.

这只狗警醒地守护着这所房屋.

5. All but one of these letter bombs had been intercepted by vigilant post office staff.

除了一封漏网之外，警惕的邮局员工截获了其余所有的邮件炸弹。