英文關鍵字
water
large
pile
dam
pipe
pipeline
piping
pollution
pumping
pure
reinforced
relief
rust
rusted
rusty
stack
steel
straight
stream
technology
tube
waste
run
brown
motion
corrode
corrosion
drain
ecology
environment
fall
flood
movement
flow
fluid
fold
hole
industrial
industry
jet
junk
liquid
metal
flowing
waterfall
river
flows
pipes