Ключевые слова: 3d, academic, background, blackboard, blurred, board, cartoon, chalkboard, character, class, classroom, concept, discussing, education, educational, exam, explaining, front, happy, illustration, instructor, knowledge, learn, learning, lecture, lesson, male, man, people, pointing, portrait, presentation, presenting, professor, research, school, science, scientist, showing, smart, smiling, standing, student, study, teacher, teaching, test, training, university,