英文關鍵字
circle
clean
dirty
facility
factory
filter
machine
pattern
plant
pollution
pond
pool
pump
round
sanitary
sanitation
settle
sewage
smelly
stink
treatment
waste
water
英文關鍵字
circle
clean
dirty
facility
factory
filter
machine
pattern
plant
pollution
pond
pool
pump
round
sanitary
sanitation
settle
sewage
smelly
stink
treatment
waste
water