Ключевые слова: advertisement, advertising, background, blackboard, blank, board, chalk, chalkboard, childhood, closed, closeup, communication, concept, copy, copyspace, desk, dirty, drawing, education, empty, frame, green, hanging, information, learn, learning, lesson, message, nobody, not open, note, notice, office, old, schedule, school, sign, space, study, table, teach, teaching, text, used, wood, wooden, word, write,