Explain the main differences and similarities of the three spirits in A Christmas Carol.

You have asked quite a big question here, and the best way
to answer it is to compare and contrast the way that the text introduces and describes
the three ghosts. You are right in being aware of the general symbolism of each ghost
and the time that they represent, but it is important to realize how each ghost operates
to taunt Scrooge with the kind of man that he is now and with regret and remorse over
his past, present and future actions.

The Ghost of
Christmas Past is described as being:

readability="10">

...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.

It is perhaps
fitting then that the ghost that examines the past and the actions and choices that have
led Scrooge to become the man that he is today appears in such a way that its very
appearance depicts looking back on our past lives and
decisions.

The Ghost of Christmas Present is described in
such a fashion as to emphasize the season of plenty and the festival that he
represents:

readability="12">

...there sat a jolly Giant, glorious to see; who
bore a glowing torch, in shape not unlike Plenty's horn, and held it up, high up, to
shed its light on Scrooge, as he came peeping round the
door.

Perhaps this
description is fitting for the Ghost that shows so many people enjoying the season and
all of the luxuries and warmth and festivities that come along with
it.

Lastly, the Ghost of Christmas Yet To Come is described
in such a way as to emphasize its darkness and associations with
death:

It was
shrouded in a deep black garment, which concealed its head, its face, its form, and left
nothing of it visible save one outstretched hand. But for this it would have been
difficult to detach its figure from the night, and separate it from the darkness by
which it was
surrounded.

Again, the point
of this Ghost is to show how Scrooge is remembered after his death, and to shock him
with how little respect and regard he had even from those he considered his "friends"
and "business associates." Thus the darkness and the "solemn dread" that this Ghost
inspires in Scrooge is perhaps fitting.

Key to
understanding these Ghosts is considering the way they are described and the scenes that
they show Scrooge. I hope I have given brief indications of how each of the Ghosts
operate. Good luck!