The most important thing ____ when ____an emergency is to stay calm.
| A．keep it in mind; deal with | B．keep in mind; dealing with |
| C．to keep it in mind; dealing with; | D．to keep in mind; dealing with |
.
About 71% of the earth’s surface ______ covered with water, but 20% of the world population ______ have access to safe drinking water.
| A．is; doesn’t | B．are; don’t | C．are; doesn’t | D．is; don’t |
.
— Have you thought of a theme for your poster yet?
— No, I ______ a lot about it, but I haven’t decided.
| A．will think | B．have been thinking | C．had thought | D．was thinking |
.
______ left before the deadline, it doesn’t seem likely that John will finish the job.
| A．Though such a short time | B．Because such a short time |
| C．With such a short time | D．As such a short time |
.
Medical ______ shows that men are more likely to have heart attacks than women.
| A．expectation | B．evidence | C．experience | D．exchange |
.
Several years had passed ______ I finally realized the true value of friendship.
| A．when | B．that | C．after | D．before |