Why don't you give your mouth a rest?

Why don't we drop over to see her?

Why don't you dine out with me for a change?

Why don't you look it up in the phone book?

That is why so many people are suffering from famine.

In the first place, why do the birds migrate at all?

I figured out why the machine wouldn't work.

That is why he did not agree to what they had proposed.

I wonder why John is always late for school.

Why don't you share your cookies with Jim?