本程序主要实现的是：一个打字练习的小游戏。运行程序之后，屏幕是会随机出现一个字符，然后用户根据这个字符敲击键盘上的相应字母，如果二者吻合（称为命中）则分数增1，否则分数减1。此外，如果超过了一定的时间用户还未按键，则分数也减1。-The main achievement of this process is: a typing practice game. After running the program, the screen will be a random character, and then the user based on the characters on the keyboard corresponding letters, if the two match (called hit) by the scores of 1, otherwise score by 1. In addition, if more than a certain amount of time the user keys have not yet, then scores are also minus 1.