VOA慢速英语:如何制作自己的口罩

caught off guard expression : to be surprised by something unexpected

tip –n. a piece of advice or useful information

comfortably –adj. done with no physically unpleasant feelings

recommend –v. to suggest that someone do (something)

sew –v. to make or repair something using a needle and thread

fabric –n. a material like a cloth

bleach –n. a strong chemical that is used to make something clean or white

respirator –n. a device worn over the mouth and nose that aids breathing when there is a pollutant in the air

tuck –v. to push the end of (something, such as a piece of cloth or paper) into or behind something in order to hold it in place, make it look neat, etc.