英文關鍵字
sewer
coming
up
sand
water
drain
environment
wet
flow
supply
tap
summer
toxic
treatment
tube
valve
urban
wastewater
clean
air
stream
city
closeup
hole
hot
manhole
rural
grid
road
beach
pressure
waste
pouring
industrial
smelly
steam
polluting
pump
pipe
splash
pipeline
flowing
liquid
working
equipment
industry
slow
motion