• The Past Perfect Progressive tense shows that an action that started in the past continued up until another time in the past.
• The Present Perfect Simple is used to describe an action or situation that started in the past and continues in the present.
• The Future Unreal Conditional is used to talk about imaginary situations in the future.
A Tense Christmas
The Ghost of Christmas - Past Perfect Progressive
Midnight. Awoken by a ghost.
I thought I must be raving.
But then he went and showed me
How badly I'd been behaving.
The Ghost of Christmas - Present Perfect
The next night, a ghost again:
with a much more recent scene
More evidence piling up of how
unpleasant I have been.
The Ghost of Christmas - Future Unreal Conditional
A final late night ghostly vision.
But this one lacked the pain and strife
I saw if I could be a kinder man,
I would create a better life.
Source: Brian Bilston