Ключевые слова: background, blue, bolt, build, concrete, connection, construction, control, crane, ecology, energy, engineering, equipment, factory, faucet, fuel, gas, gasoline, heat, industrial, industry, line, machine, manual, manufacturing, metal, natural gas, pipe, pipeline, plant, power, pressure, rusty, service, station, steel, system, tap, technology, transportation, tube, valve, wheel, work, worker, yellow,