Rehearse the moves of tightening an airmask and securing a flotation vest.
演练戴紧防毒面具和固定安全背心。
2
Many noted that he walked outside on such a heavily polluted day without an airmask.
许多网民指出，他在污染如此严重的一天来到室外，还没有戴口罩。
3
Often, the first treatment doctors will recommend is a Continuous Positive airway Pressure (CPAP) device, a specially designed nasal mask that blows air directly into your airways.