Ключевые слова: abstract, accept, agree, allow, answer, approve, approved, background, backgrounds, black, blackboard, check, checkmark, choice, confirm, correct, decide, decision, draw, drawing, eduction, false, good, icon, mark, no, ok, okay, pass, positive, presentation, right, school, select, selection, sign, student, study, symbol, teacher, true, write, writing, yes,