Ключевые слова: advice, black, blackboard, board, business, chalk, chalkboard, change, clean, condition, dark, education, guidance, guideline, hand, handwriting, idea, information, instruction, knowledge, law, message, messy, new, new rules, notice, office, organization, policy, quarantine, regulation, requirement, rule, school, school learning, sign, standard, student, text, update, white, word, work, writing,