Ключевые слова: 10 years, 1012 years, 11 years, 12 years, american, boy, caucasian, child, childhood, class, classmate, classroom, cognition, concentration, education, elementary, european, french, german, group, indoor, inside, intelligent, junior, kid, knowledge, learning, lecture, lesson, listening, male, person, primary, pupil, room, school, schoolboy, schoolkid, schoolwork, sitting, smart, student, studying, teacher, teen, teenager, young, youngster,