Ключевые слова: advice, air pollution, blue, communication, construction industry, danger, day, direction, electricity, environment, environmental conservation, environmental damage, equipment, factory, fence, forbidden, forest, fuel and power generation, grass, green color, hazardous area sign, industry, information sign, leaf, metal, nature, no people, nuclear power station, outdoors, physical structure, plans, poisonous, pole, pollution, power supply, radiation, risk, road sign, road warning sign, safety, sign, smoke, symbol, toxic waste, traffic, tree, warning sign, warning symbol, yellow,