英文關鍵字
bathroom
chrome
clean
construction
contamination
danger
dirty
discharge
drain
drainage
drop
dump
ecology
environment
environmental
equipment
factory
flow
flowing
garbage
industrial
industry
lake
liquid
metal
natural
nature
ocean
outdoor
outdoors
pipe
pipeline
plant
pollution
pond
pump
reflection
river
sewage
sewer
shiny
silver
stream
tap
toxic
treatment
tube
unhygienic
waste
water