21、Hours of playing violent video games can affect the way the brain works, ______ damage to certain cells of brain and slowing brain activity.

     A. to cause                   B. causing             C. cause                       D. caused

20、As the visiting prime minister puts, China’s influence in the world will continue to strengthen ______ its economy grows.

     A. although             B. until                C. as                  D. before

19、Yesterday evening the board had a discussion regarding ______ they should set up more scholarships to meet the increasing demands.

     A. what           B. whether       C. that              D. who

18、Indeed the best leading actor has read a lot of books, but the best supporting actress has read no ______.

A. more                  B. few            C. less              D. little

17、--- John, tell me the truth. When did you tell Bill the assignments?

--- The moment he ______ back home.

     A. came                  B. come         C. comes            D. will come

16、Many introduced plants ______ be cultivated in special soils for some time before they are transplanted in the field, otherwise they won’t survive.

A. must                    B. might              C. could                          D. would

15、Knowing the meaning of a word is one thing; yet using it both grammatically and communicatively properly is quite ______.

A. much               B. many            C. little                D. another

14、With the guide leading the way, the visitors were able to travel through the forest _____ foot.

A. by                           B. on                    C. in                            D. with

13、进了这所寄宿制学校(boarding school)后我才意识到自己以前是多么依赖父母。 （Not until）

二、选择题

（每空分，共分）

12、由于一系列新的地铁线路的开通，我市公共交通状况有了很大改善。(Due to)