static void Main(string[] args) { //Beverage beverage = new Espresso(); //Console.WriteLine(beverage.getDescription() + " $" + beverage.cost()); Beverage beverage2 = new HouseBlend(); beverage2 = new Mocha(beverage2); beverage2 = new Mocha(beverage2); beverage2 = new Whip(beverage2); // 这里会有问题 Beverage的getDescription是个实体函数. string strDescription = beverage2.getDescription(); Console.WriteLine(strDescription + " $" + beverage2.cost()); }