Ключевые слова: advertisement, advertising, announcement, background, billboard, black, blackboard, blank, board, business, chalk, chalkboard, class, classroom, close, communication, concept, copy, copyspace, dirty, drawing, education, empty, frame, green, grunge, horizontal, learn, learning, lesson, message, nobody, note, old, remember, school, sign, space, student, study, symbol, teach, teacher, text, texture, textured, used, white, wooden, write,