1. 编制应用程序，让一个小球在客户区匀速移动，当碰到边界后反弹。 学有余力的同学可尝试模仿课堂演示完成用键盘控制挡板反弹小球，小球碰到砖块则把砖块打掉。 -1. Preparation of the application, so that a uniform ball moving in the client area, when it comes to the border after the rebound. Studies have spare capacity to t