Ключевые слова: abstract, app, art, background, book, business, communication, computer, concept, course, creative, design, education, elearning, flat, graduation, icon, idea, illustration, information, internet, knowledge, laptop, learn, line, marketing, mobile, network, object, online, outline, school, science, service, set, sign, social, student, study, symbol, teaching, technology, training, tutorial, university, web,