Ключевые слова: 30s, academic, adult, back, background, board, book, caucasian, chalkboard, cheerful, childhood, children, class, classroom, college, communication, desk, education, educator, elementary, helping, knowledge, learn, learning, lesson, men, person, portrait, professor, pupil, school, schoolboy, sitting, smiling, student, students, study, studying, table, teacher, teaching, technology, teen, teenage, teenager, training, tutor, university,