Ключевые слова: background, black, blackboard, blank, board, business, chalk, chalkboard, check, checklist, class, clipboard, communication, concept, copy, design, do, drawing, education, empty, form, future, illustration, information, letter, list, memo, message, note, object, office, plan, remind, school, shape, space, square, study, studying, teach, text, texture, used, white, words, work, write, writing, written,