The general had 20/20 hindsight about the defeat, but no foresight at all.

An old belief is sometimes still widely current.

Never did I dream that I would take first place in the piano contest.

What if Tom hadn't heard my voice at that time? What in the world would have happened? Just thinking about it gives me the chills.

That was an unexpected event.

That was an unexpected development.

I had an experience I never thought I'd have.

I never imagined this would happen.