保持警惕，注意任何不寻常的事情。

___Keep ___your ___eyes ___open for anything unusual.

旅行时，你应该留心观察文化细节。

When traveling, you should ___keep ___your ___eyes ___open for cultural insights.

安保人员必须密切关注潜在威胁。

Security personnel must ___keep ___their ___eyes ___open for potential threats.