Ключевые слова: academic, adult, background, book, business, casual, caucasian, chalkboard, cheerful, class, classroom, college, confident, desk, education, educator, emotion, exam, green, indoors, information, instructor, intelligent, job, knowledge, lecture, lecturer, looking, male, man, math, occupation, one, people, person, portrait, professor, school, smart, smiling, standing, student, study, teach, teacher, trainer, training, work, working, young,