Ключевые слова: adult, bad, blackboard, board, casual clothing, caucasian, cheerful, class, classroom, college, confident, consultant, education, eyeglasses, glasses, indoor, instructor, knowledge, learn, learning, lesson, looking at camera, man, middle age, occupation, one person, person, portrait, professional, professional occupation, professor, school, standing, student, studying, talk, teacher, teaching, trainer, university, white board, whiteboard, work, young adult, young men,