英文關鍵字
between
brown
bubble
canal
circular
circulate
currents
deep
dirty
drain
ecology
environment
factory
flow
flowing
flows
fluid
garbage
grass
influence
into
liquid
motion
natural
nature
old
pollution
ripple
river
round
sewage
sewer
smell
spin
spiral
spiraling
stalks
stream
swift
swirl
terrible
the
turbulent
turning
twirl
twist
vortex
warming
waste
water
whirl
whirlpool
whirlpools