n.<正>警觉;警惕;警戒;<医>失眠症;
例句:
The price of life is eternal vigilance.
生命的代价就是永远小心谨慎.
We must never relax our vigilance.
我们决不可放松警惕.
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.