英文關鍵字
air
atmosphere
boiler
building
chimney
city
clear
climate
cold
cooling
ecology
energy
environment
exhaust
factory
gas
global
heat
heating
horizon
industrial
industry
period
pipe
pipes
pollution
power
puffy
rise
season
sky
smog
smoke
smokestack
smoking
station
steam
structure
technology
top
tower
town
tree
urban
white
winter