Ключевые слова: aeration, airing, cell, circle, component, constituent, couple, cycle, detail, duct, element, feature, fraction, galvanized sheet, industry, ingredient, make, member, metallurgy, obverse, output, outturn, part, piece, pipe, portion, principle, produce, product, production, proportion, round, section, steel, term, tube, unit, ventilation, ventilation systems, venting,