Ключевые слова: announcement, answer, ask, asking, background, billboard, black, blackboard, board, business, chalk, chalkboard, class, communication, concept, content, context, drawing, education, faq, frame, frequently asked question, grunge, illustration, information, internet, knowledge, learn, lesson, letter, message, note, question, remind, school, service, study, studying, teach, texture, used, white, word, write, www,