Ключевые слова: art, black, blackboard, chalk, chalkboard, classroom, college, communication, draw, education, element, engine, engineer, engineering, factory, gear, illustration, industrial, industry, isolated, learning, machine, machinery, math, mechanical, mechanics, mechanism, metal, middle, object, on, roll, rotate, school, secondary, sign, spin, steel, table, teacher, technical, technology, teeth, transfer, transmission, wheel, white, work, worker, workforce,