—I have a headache.

—I’m not surprised you ________ in front of the computer for too long.

A. work                        B. are working                     C. have been working        D. had worked

 The restaurant wasn’t ________ that other restaurant we went to.

A. half as good as       B. as half good as                C. as good as half                D. good as half as

The result is not very important to us, but if we do win, then so much ________.

A. the best                          B. best                                   C. better                              D. the better

         —Did you ask Tom for help?

—I ________. —I managed perfectly well on my own.

A. needn’t have                  B. don’t need to                 C. didn’t need to                 D. needn’t

         —Try not to work yourself too hard. Take it easy.

—Thanks. ________.

A. So what?                          B. No way                    C. What for                          D. You too

In Dali Mr Green was so struck by the beauty of _____nature that he stayed for _____third week.

A.the ; the    B. the ; a   C. 不填；the    D. 不填；a

The research is so designed that, once _______, nothing can be done to change it.

A. begins         B. having begun       C. begun D. Beginning

The bell _______ the end of the period rang, _______ our heated discussion.

A. indicated; interrupting                                       B. indicating; interrupting

C. indicating; interrupted                                       D. indicated; interrupted

_______ to sunlight for too much time will do harm to one’s skin.

A. Being exposed                                                     B. Exposed

C. Having exposed                                                   D. After being exposed

_______ in the queue for half an hour, Tom suddenly realized that he had left his wallet at home.

A. To wait          B. Having waited     C. Have waited   D. To have waited