Ключевые слова: advertising, announcement, background, billboard, black, blackboard, blank, board, brown, chalk, chalkboard, class, classroom, clean, closeup, communication, copy, draw, drawing, education, empty, frame, horizontal, isolated, kid, learn, lesson, memo, message, nobody, object, pattern, presentation, school, sign, space, surface, teach, teacher, text, texture, white, wood, wooden, work, write,