He wishes the accident hadn't happened.

I hadn't seen for ten years.

I hadn't realized the magnitude of the problems.

Hadn't we better go now?

Hadn't we better be going now?

Hadn't we better be going soon?

He looked as if he hadn't eaten for days.

I hadn't bargained on such a heavy traffic jam.

He hadn't prepared for the test; still he passed it.

Up to last week, I hadn't received a reply.