C#继承公共接口的实例，实现思路：Program program = new Program() 实例化类对象，使用派生类对象实例化接口ITeacher，使用派生类对象实例化接口IStudent。-C# inherits the public interface instance, realization of ideas: Program program = new Program ()　instantiated class object, using the derived class object is instantiated interface ITeacher, using the derived class object is instantiated interface IStudent.