[jǐng tì]
be on guard against; watch out for; be vigilant; be on the alert
maintain sharp vigilance
保持高度警惕
exercise the highest vigilance
百倍警惕
relax vigilance
放松警惕
drop one's guard; be off one's guard
丧失警惕
heighten our vigilance and defend our motherland
提高警惕， 保卫祖国
be vigilant against enemy sabotage
警惕敌人的破坏
Constant vigilance is necessary in order to avoid accidents.
为了避免意外事故， 必须经常保持警惕。