英文關鍵字
water
pipe
dirty
waste
environment
sewage
river
pollution
industry
industrial
flowing
flow
drain
tube
stream
ecology
sewer
pipeline
liquid
treatment
drainage
canal
environmental
substance
nature
tunnel
sewerage
old
toxic
garbage
floodwater
contaminate
fluid
sluice
unclean
catchment
contamination
pipes
danger
polluter
culvert
pollute
polluting
runoff
waterway
wastewater
drainpipe
flood
polluted
round
disaster