最后一步出问题的同学们，你们如果报错Setting the parent of a transform which resides in a prefab is disabled to prevent data corruption.的话，就是因为Board.cs的crossObj.transform.SetParent(gameObject.transform);
crossObj.transform.localScale = Vector3.one;
这两行应该是小写，实例化后的对象，而不应是大写的类
