VOA慢速英语:该不该戴口罩?

droplet - n. a very small drop of liquid

tough - adj. very difficult to do or deal with

tight - adj. difficult to move : fastened, attached, or held in a position that is not easy to move

surgical - adj. of or relating to the process of performing a medical operation

global - adj. involving the whole world

sew - v. to make or repair something (such as a piece of clothing) by using a needle and thread