It is still a mystery why he suddenly left the town.

I can't figure out why he did it.

The reason why he left the tennis club is obscure.

The reason why he came so early is not evident.

If he was to return at seven o'clock, why didn't he?

Why don't you strike out on your own?

Why do you think animals dread fire?

Can you explain why you were late?

Do you wonder why no one trusts him?

Why don't you have your bath now?