英文關鍵字
air
atmosphere
background
boy
catastrophe
caucasian
chemical
chimneys
china
choke
concept
cough
damage
danger
dirty
disaster
ecology
environment
equipment
factory
gas
gasp
global
guy
hazard
health
human
ill
industrial
industry
kid
male
man
mask
outdoors
person
pipes
plant
poisonous
pollutant
pollution
protect
protection
respirator
safe
smoke
toxic
urban
wear
young