Ключевые слова: abstract, academic, adult, audience, background, blur, blurred, boardroom, business, businessman, center, coaching, concept, conference, congress, convention, corporate, crowd, education, educator, event, explaining, forum, group, hall, indoors, information, institute, knowledge, learn, lecture, light, listeners, listening, man, meeting, participants, people, person, presentation, professional, public, room, seminar, sitting, speaker, speech, study, teaching, training,