Ключевые слова: adult, bad, board, casual clothing, caucasian, cheerful, child, class, classroom, college, confident, education, explaining, indoor, knowledge, learn, learning, lesson, man, mid adult, middle age, occupation, person, portrait, professional, professional occupation, professor, school, schoolchildren, schoolgirl, standing, student, studying, talk, teacher, teaching, university, white board, whiteboard, work, young adult, young men,