6) How does the Ghost of christmas yet to come compare with the other two spirits?....................... and why do you think dickens does this?

Each ghost has a symbolic representation with the time they represent. The Ghost of Christmas Past is described,

like a child: yet not so like a child as like an old man, viewed through some supernatural medium, which gave him the appearance of having receded from the view, and being diminished to a child's proportions.

He represents the choices that Scrooge had made in his childhood to adulthood. The ghost is there to have Scrooge reflect on his past: the things that made him truly happy and the mistakes he made. The Ghost of Christmas Past is not jolly like the Ghost of Christmas Present, nor is he a solemn specter like the Ghost of Christmas future. He is there to remind Scrooge of another time when Scrooge might have changed the course of his life.