Ключевые слова: advanced, average, beginner, button, competence, control, design, development, education, efficiency, element, enhance, experienced, expert, expertise, gauge, graphic, growth, high, illustration, improve, job, knob, knowledge, learn, level, mastery, maximum, measure, measurement, motivation, object, perfect, professional, proficiency, progression, result, skill, skilled, skillful, specialist, success, switch, symbol, technology, test, text, training, word,