Ключевые слова: book, business, cap, certificate, class, collection, college, communication, computer, concept, course, design, digital, diploma, education, elearning, flat, graduation, icon, illustration, knowledge, learn, learning, lesson, library, line, microscope, online, outline, people, pictogram, school, seminar, set, sign, stroke, student, study, symbol, teacher, technology, test, thin, training, tutorial, university, video, web, webinar,