英文關鍵字
air
boy
building
catastrophe
chemical
chimneys
choke
climate
cough
damage
danger
dangerous
dirty
ecological
ecology
energy
environment
equipment
factory
flu
gas
gasp
global
guy
headache
health
human
illness
industrial
industry
kid
male
man
mask
one
person
pipes
plant
pollution
problem
protection
protective
respirator
safe
smoke
standing
toxic
virus
wearing
young