Why don't you give tennis a try?

Why don't you stop by for a little while?

Why don't you come dancing with me?

Nobody knows why he left the town.

Why don't you give up smoking?

That's why I told you not to go by car.

That's why I told you not to go by yourself.

That's why I was absent from school yesterday.

That is why women keep their career without marriage.

The boy told me why he was crying.