Ключевые слова: activity, air, building, business, climate, cloud, concepts, condensation, danger, employment, energy, equipment, exterior, factory, fumes, gas, generation, global, industry, medicine, natural, nobody, organism, outdoors, ozone, pollution, power, silhouette, sky, smog, smoke, snow, structure, substance, sunset, technology, tower, toxic, twilight, warming, water, winter,