Subject + 警惕 + 着 + Object
The verb 警惕 (jǐngtì) means to be vigilant, alert, or on guard against potential danger. It implies a heightened state of awareness and caution. For example, 警惕着外面的动静 means "to be on guard against movement outside."
出门在外要警惕陌生人的搭讪。
Chūmén zài wài yào jǐngtì mòshēngrén de dāshàn.
When you're out and about, be wary of strangers striking up conversations.
他对周围的环境保持着高度的警惕。
Tā duì zhōuwéi de huánjìng bǎochí zhe gāodù de jǐngtì.
He maintains a high level of vigilance toward his surroundings.
最近诈骗案很多,大家一定要提高警惕。
Zuìjìn zhàpiàn àn hěn duō, dàjiā yīdìng yào tígāo jǐngtì.
There have been many fraud cases recently; everyone must stay alert.