as到底干嘛了???

    string a = "A";
            string[] Ff = { "A", "B", "C" };
            var ret=Ff as IList;
            Console.WriteLine(ret.GetType());
            Console.WriteLine(ret.Contains(a));
            Console.Write("Press any key to continue . . . ");
            Console.ReadKey(true);

上面输出了什么结果?