機器
asphalt
broom
brush
city
clean
cleaner
cleaning
cleanliness
cleanup
closeup
day
dirt
dirty
dust
environment
equipment
floor
garbage
industrial
industry
land
machinery
mechanization
motion
municipal
nobody
outdoor
outdoors
pavement
road
rubbish
sanitation
service
sidewalk
street
street sweeper
sweep
sweeper
sweeping
technology
transportation
truck
urban
vacuum
vehicle
waste
wheel
work
working