static class Program { static void Main() { Work.Run(); Console.Read(); } } //在program类下海应该有个Work的类和Run方法 public class Work { public static void Run() { string Title = "*****************************************************"; Title += "\n1.加法"; Title += "\n2.减法"; Title += "\n3.乘法"; Title += "\n4.除法"; Title += "\n5.退出"; Title += "\n*****************************************************";