___ the invention of the steoriginated in

What if you_____ to send an essay with your application?一I would have been rejected．

This painting is so valuable that it is rather difficult to calculate _______ its price would be if the museum _______ to sell it.

I can’t believe _____ a little girl can read _____many books.

Look at these black clouds.It________soon.—Sure.If only we________out.[ ]