Ключевые слова: abstract, agree, alternative, answer, background, black, blackboard, blank, board, business, chalk, chalkboard, check, checkbox, choice, concept, count, decision, design, disagree, drawn, drawning, education, election, exam, hand, idea, illustration, information, isolated, learning, list, message, negative, no, positive, problem, school, sign, solution, survey, symbol, test, text, tickbox, vote, voting, white, write, yes,