Do you know the reason ____ he was late?

If he ____ on tourists for his business,he would have to close his shop.

What is Bill going to do?

The ____ populated area was a breeding place forinfectious diseases.

Mary keeps talking about the party.She had a very good time,______she?

—Have you finished the work?

—Not yet, but no matter how hard it is, we'll keep ___ until we make it.

Physics is the present day equivalent of ____ used to be called natural philosophy, from ____ most of present day science arose.

Louise: Will 100 dollars be enough?

Jack: Another 50 ______.

I don’t know ______ a show. Can you tell me?

"Look what you've done!You ______more careful."