C# 4.0中dynamic的作用

　　 internal sealed class Coffee
    {
        public string GetName()
        {
            return "You selected Maxwell coffee.";
        }
    }

    internal sealed class Juice
    {
        public string GetName()
        {
            return "You selected orange juice.";
        }
    }

　　 internal sealed class DynamicDemo
    {
        public static void Main()
        {

            Console.WriteLine("Please Select Your Drink:1--Juice;2--Coffee");

            var nDrinkRead = Console.Read();

            dynamic drink = GetDrink(nDrinkRead);

            Console.WriteLine(drink.GetName());

            Console.Read();
        }

        private static object GetDrink(int i)
        {
            if (i == ) return new Juice();
            return new Coffee();
        }
    }