VOA慢速英语:你是否需要带口罩?

mask –n. something that covers part or all of the face

calculation –n. careful thought or planning through a process

filter –n. a device or process that removes something unwanted

perception –n. the way a person thinks about or understands something

involuntary –adj. not done by choice

scary –adj. causing fear

log off –n. to suspend a connection with a computer network