英文關鍵字
approach
background
city
communication
device
distance
dust
epidemic
europe
female
filter
filtration
girl
gray
infection
internet
looking
mask
message
mobile
online
person
phone
pneumonia
pollution
prevent
prevention
protect
protected
protection
protective
quarantine
respiratory
smartphone
spreading
street
uninhabited
unrecognizable
urban
virus
wearing
woman