ActionScript - 如何通过if语句条件从屏幕中删除项/对象

I am trying to make a drag and drop game, basically I have three conditions, if the dragged item is placed on a target which is not what it should match then take the user to another frame (game over), however if the item that is placed matches with the target then just place the item on top of the target. I am trying to make a drag and drop game, basic