英文關鍵字
aftermath
background
bad
brown
catastrophe
chemical
civilization
clean
damage
dangerous
day
dense
dirt
dirty
dump
dynamic
ecology
environment
factory
float
garbage
green
harm
hazard
industrial
industry
lake
layer
level
liquid
litter
movement
mud
nature
piece
pollute
pollution
pond
river
sewage
sewer
substance
surface
texture
toxic
trash
unhygienic
waste
water
wood