Bamboo line graph, also known as bar graph and bar graph, originated in Europe and America. The horizontal axis represents time and the vertical axis represents price. The vertical bar is the connection between the highest price and the lowest price in a trading day. The short line on the left side of the vertical bar indicates the daily opening price, and the short line on the right side of the vertical bar indicates the daily closing price. At present, there are fewer exams, and the latest version of textbooks has also been deleted. There are many time-sharing charts, minute-transaction charts and K-line charts in the futures examination. 832