兩個object為什么不相等??

using System;

class Test

{

     static void Main() {

           string s = "Test";

         string t = string.Copy(s);

         Console.WriteLine(s == t);

         Console.WriteLine((object)s == (object)t);

     }

}

产生输出

True

False

為什么((object)s == (object)t)不等於true;