@RidleyDM @DrLeanaWen One thing I've noticed that is extremely odd is that types of masks seems to vary so much from place to place, definitely by city and over time and even sometimes by neighborhood.
@RidleyDM@DrLeanaWen我注意到一件非常奇怪的事情，就是面具的类型似乎因地而异，肯定是因城市和时间的推移，有时甚至因社区而异。