Ключевые слова: adult, black, blackboard, blank, calendar, caucasian, chalk, chalkart equipment, chalkboard, chalkboard visual aid, closeup, concepts, day of week, dirty, english, finger, hand, handwriting, handwritten, indoors, inscription, left hand, letter, man, message, name, removal, saturday, semierased, smear, smudged, text, unsharp, word, yellow,