Ключевые слова: adult, arm, background, black, blackboard, board, chalk, chalkboard, charts, clear, communicate, communication, concept, conceptual, dark, data, drawing, education, female, graphs, hand, holding, indoors, information, learn, lesson, manual, message, outdated, plan, point, pointing, present, round, scribble, show, sketch, space, strategy, teach, texture, touch, way, white, woman, write, writing, written, young,