英文關鍵字
concrete
sewer
drainage
collector
filled
water
round
plastic
pipe
connected
storm
drain
culvert
abstract
architecture
background
canal
channel
city
civil
construction
creepy
dark
deep
dirty
system
ecology
empty
engineering
exit
exploration
exploring
flow
flowing
industrial
inside
light
old
perspective
pipeline
plant
pollution
rectangular
river
sewage
sewerage
stream
tube
tunnel
underground
urban
waste
wastewater