必须保持

• While danger threatens we must all be on guard
  危险正逼近，我们必须保持警惕。
• Everyone must keep quiet once the exam begins
  一旦开始考试，大家就必须保持安静。
• They must communicate rapidly in any case
  在任何条件下必须保持通信联络迅速。
• So we ' re just gonna put little smiles on our faces
  所以我们脸上必须保持一点微笑
• To play taijiquan , you have to keep a quiet mind
  打太极拳时，你必须保持内心平静。
• You must stay wide - awake against possible dangers
  你必须保持警惕,防止可能的危险。
• And you have to remain cool in the challenge , in the moment
  在冲突中你必须保持冷静
• To stay in division 1 , you must place 6th or better
  要留在第1区，你必须保持前六名。
• If he is unconscious , keep his airway unobstructed
  如伤病者昏迷，必须保持气道畅通。
• And you have to remain cool in the challenge , in the moment
  在冲突中你必须保持冷静