Ключевые слова: adult, background, blackboard, book, caucasian, chalkboard, check, classroom, close up, college, concentrated, concept, education, end, exact, explanation, eyeglasses, finish, formal, formula, full, glance, glasses, handsome, knowledge, lesson, let, look, man, math, mathematics, me, mistake, pile, professor, school, science, see, smart, study, suit, symbol, teach, teacher, university, unshaven, vision, wear, wonder, written,