英文關鍵字
sewage
water
pollution
pipe
sewer
garbage
dirty
muddy
drain
waste
tree
trash
plastic
environment
river
industry
flowing
tube
ecology
drainpipe
fluid
toxic
drainage
liquid
contamination
wet
texture
pipeline
stream
concrete
danger
hole
pouring
plant
rust
problem
factory
cement
splash
untreated
body
effluents
effluent
city
green