Ключевые слова: background, board, book, business, class, coach, college, computer, course, demonstrate, digital, diploma, ebook, education, exam, icon, illustration, internet, knowledge, learn, lecture, lesson, lessons, library, line, online, outline, person, school, science, seminar, set, sign, stroke, student, study, symbol, teach, teacher, trainer, training, university, video, web, webinar,