vigilance [ˈvɪdʒələns]

例句:

• But now an outward vigilance was required, too.
  来自NEWYORKER
• Drugs are a problem that requires constant vigilance.
  需要对毒品问题长期保持警惕。
  
• The birds cannot afford to relax their vigilance against predators.
  鸟儿不敢放松对捕食者的警戒.
  
• Never relax your vigilance while you live in peace.
  你们要居安思危.
  
• It's a matter of vigilance and common sense.
  来自SA
• That is the risk, and vigilance is essential.
  来自BBC