Ключевые слова: adult, alone, attractive, board, brush, caucasian, chalk, chalkboard, cheerful, class, classroom, clean, clear, cognition, college, communication, complexity, confident, contemplation, drawing, duster, education, elementary, erasing, explain, female, formulas, high school, indoors, instructing, intelligence, job, lecture, lesson, marker, mathematics, meeting, occupation, one person, profession, school, smiling, sponge, student, teacher, text, university, white board, whiteboard, woman,