The boys _______themselves last night, did they? A enjoyed B didn’t enjoy C haven’t enjoyed D have enjoyed
These photos _______ by my sister on Mount Tai last summer.
—May I play computer games, Mum? —No, you ______. You’ve got a lot of homework to do.
Mike and I _______ net-friends. We talk on-line every week.
—Which car is _______, the yellow one or the red one? —The red one, I think.
— _______ does Earth Day come every year? —It comes on April 22.