Ключевые слова: addition, adult, answer, beginner, blackboard, board, boy, chalkboard, chemical, chemistry, child, children, classroom, clever, consulting, copybook, education, element, elementary, explaining, female, hand, help, holding, homework, kid, knowledge, learn, lesson, letter, modern, people, person, pointing, primary, pupil, school, schoolboy, schoolchildren, schoolkid, showing, solution, solve, study, teacher, woman, young, youngster, youthful,