Ключевые слова: ad, advert, advertisement, advertising, background, billboard, black, blackboard, blank, board, chalk, chalkboard, class, classroom, close, college, communication, concept, continuing, copy, copyspace, dirty, drawing, education, empty, frame, grunge, handwriting, information, learn, lesson, message, note, old, school, sign, space, student, symbol, teacher, teaching, text, texture, university, up, used, vertical, white, write,