Often in spoken English, I see one sentence or phrase "set up" another much like an interjection. For example:
I forgot to ask. Did you find that book I told you about?
How do you generally punctuate this? I've seen a comma used for this, but I that's only correct if it can be argued that I forgot to ask is a proper interjection (can it be?).
Should I use a colon? Semi-colon? Does it matter?