英文關鍵字
background
build
canal
cement
clean
concrete
conduit
construction
corrosion
danger
deep
dirt
dirty
drain
drainage
drainpipe
dump
ecology
environment
equipment
excavator
flow
flowing
fluid
garbage
ground
hole
industrial
industry
infrastructure
liquid
nature
old
piled
pipe
pipeline
pollution
river
sewage
sewer
sewerage
shore
stream
toxic
treatment
tube
wall
wash
waste
water