英文關鍵字
abstract
air
background
blue
business
chemical
chimney
clear
close
construction
dioxide
ecology
electricity
energy
environment
exhaust
factory
fuel
fume
gas
generation
generator
global
heat
high
industrial
industry
large
line
metal
objects
pipe
plant
pollution
power
sky
smoke
station
steam
summer
sunlight
supply
technology
tower