—What’s the matter with you?—I have a________.—Maybe you should see a dentist.
--- Have you finished your work _______? ---Yes, I've _______ finished it.
great fun it is to fly in a balloon!
—It’s too hot. Would you mind _______ the door? —_______, please do it now.
It was exciting to see so many elephants__________.
—The Blacks have _________Hainan Island. —Oh,really? I have never_________there before.