Ключевые слова: academic, academy, adult, background, bearded, blackboard, board, book, calculation, caucasian, class, classroom, college, communication, confident, course, education, explaining, formula, glasses, happy, indoors, intelligence, knowledge, learn, lecture, lesson, male, man, marker, math, mathematics, mature, occupation, person, portrait, professional, room, school, smiling, study, teach, teacher, training, tutor, university, wall, white, whiteboard, writing,