英文關鍵字
air
atmosphere
background
bare
blue
boiler
brick
building
business
chimney
cloud
cloudy
cottage
country
ecology
emissions
energy
environment
environmental
evening
exterior
fume
fuming
global
heat
heating
industrial
nature
pipe
pipes
pollution
power
sky
smog
smoke
smokestack
smoking
stack
station
technology
tree
village
warming
winter