英文關鍵字
atmosphere
blue
building
chemical
clouds
co2
color
construction
danger
depots
diesel
dock
dusk
ecology
emission
emissions
energy
engine
environment
environmental
equipment
exhaust
factory
fog
fuel
gasp
generate
generator
global
grey
harmful
industrial
industry
locomotive
machines
pollution
power
rail
railroad
railway
red
sky
smoke
station
steam
steel
suffocation
technology
toxic
train
transport
transportation