機器
change
chemical
climate
condition
connection
contamination
cool
disaster
dusk
electricity
end
engineering
exploration
factory
flowing
fossil
fuel
gas
gasoline
glasses
global
graffiti
group
grunge
heat
heavy
horizontal
huge
liquid
network
no people
oil
pollution
power
problem
production
pump
refinery
splash
spray
stream
structure
supply
time
toxic
transportation
tube
warming