Ключевые слова: advertising, aged, alphabet, best, black, blackboard, blank, board, business, chalk, chalkboard, class, classroom, college, communication, concept, dirty, drawing, educate, education, empty, erase, exam, good, grade, grunge, information, knowledge, learn, learning, lesson, letter, mark, message, note, old, performance, plus, positive, reminder, results, school, score, scratch, sign, space, stains, student, study, studying, success, surface, symbol, teach, teacher, test, texture, unclean, university, used, vintage, wall, white, write, writing,