Ключевые слова: ad, advert, advertisement, advertising, background, billboard, blackboard, blank, board, chalk, chalkboard, class, close, communication, concept, copy, copy space, copyspace, drawing, education, empty, green, handwriting, learning, lesson, message, new, note, old, school, sign, space, student, symbol, teacher, teaching, text, texture, up, used, wall, white, write,