Ключевые слова: black, blackboard, blank, board, chalk, chalkboard, classroom, clean, cleanse, clear, college, concept, copyspace, correction, damp, detail, dirty, drawn, duster, educated, elementary, equipment, eraser, fingers, hand, knowledge, object, raised hand, red, school, scrub, space, sponge, teach, text, wash, wet sponge, white, wipe, write,