二、单项填空（共15小题，每小题1分，满分15分）
从A、B、C、D四个选项中，选出最佳选项，并在答题卡上将该项涂黑。
21. —How about _______ controlled breeding program the US government began to save the red wolf?
—I should say it was _______ success; you see its number has increased.
A. a; a B. the; a C. a; 不填 D. the; 不填
22. —Linda didn’t invite us to her birthday party.
—_______? I don’t care.
A. For what B. So what C. What’s on D. What’s up
23. To her joy, Della earned first the trust of her students and then _______ of her colleagues.
A. one B. ones C. those D. that
24. More highways have been built in China, _______ it much easier for people to travel from one place to another.
A. having made B. made C. to make D. making
25. It is not always easy for the general public to see _______use a new invention can be of to their daily life.
A. which B. what C. that D whose
