Ключевые слова: adult, ask, assistance, blackboard, board, casual, caucasian, chalk, chalkboard, class, classroom, college, concept, confusion, contemplate, contemplation, decision, doubt, expressive, facial, faq, front, handsome, handwriting, handwritten, interrogation, learning, male, man, mark, message, people, person, problem, question, school, search, sign, solution, studying, symbol, teacher, think, thinking, thought, thoughtful, uncertainty, word, young,