是运用VB.NET来开发的小型算术测试系统。能够实现，随即出20道题目。并且规定在1分钟内做完，没完成的话，自动停止，进行计分-Is to use VB.NET to develop a small arithmetic test systems. Can be realized, then the 20 topics. And provides finished in one minute, did not complete, then automatically cease, to carr