Ключевые слова: adult, blank screen, blur, broadcast, brunette, caucasian, chalkboard, classroom, content, copy space, course, device, digital camera, digital tablet, distance, education, elearning, electronic, eyeglasses, gadget, gesture, indoors, internet, job, knowledge, lecture, lesson, math, mathematics, notebooks, one person, online, professional, remote, school, service, signs, streaming, symbols, teacher, technology, tutor, vlog, woman, work, workplace,