Ключевые слова: adjective, blackboard, board, chalk, chalkboard, class, classroom, continuous, definition, education, elementary, ending, english, exercise, form, future, grammar, grammarianpresent, indefinite, information, ing, language, learn, lesson, linguistic, note, noun, past, perfect, progressive, rule, school, sentence, simple, study, suffix, table, teach, tense, text, verb, word, work, write, writing,