Ключевые слова: advertising, aid, background, blackboard, blank, board, chalk, chalkboard, class, classroom, closeup, college, communication, day, drawing, education, empty, equipment, erase, eraser, exam, firstclass, frame, green, grunge, horizontal, information, knowledge, learning, no people, nobody, old, ready, school, scratch, student, studio, studying, symbol, teacher, teachers, teaching, texture, textured, university, used, visual, white, write,