Ключевые слова: activities, activity, additional, back, background, break, camp, child, class, college, complementary, concept, course, curricular, development, education, elective, elementary, extra, field, flower, fun, holiday, homework, improvement, intelligence, knowledge, learn, learning, lesson, meadow, nature, optional, research, school, science, skill, spring, student, study, studying, subject, teacher, text, to, training, tutor, university, wild, wisdom,