Ключевые слова: appreciation, back, background, black, blackboard, board, book, celebration, chalk, chalkboard, children, class, classroom, cognition, college, concept, congratulation, copy, day, design, drawing, education, flat, flower, graphic, green, hand, happy, heart, holiday, international, knowledge, lay, learn, lettering, national, object, poster, school, science, space, stationery, student, study, symbol, teacher, text, university, world, young,