Hopeful Bob explains how it is...

I would if I could
But I can't
So I won't
But believe me, I would if I could
But I just can't
It would be good if I could
But I can't do what can't be done
At least not right now
Maybe later
I could then
Maybe
Later that is
But just not right now
As I was saying before
Yes
Indeed
What did I say?

Drink beer be jolly