第二部分：单项填空（共15小题；每小题1分，满分15分）
从四个选项（A、B、C和D）中，选出可以填入空白处的最佳选项，并在答题卡上将该项涂黑。
21. — Nancy, you have allowed your Japanese to become less good over a period of time.
— I know. I really must ______ my Japanese before we visit Japan next year.
A. pick up B. polish up C. make up D. take up
22. Researchers have failed to find a way to treat such diseases, and it will still be years before they can find____is effective.
A. the one B. the one that C. one D. one that
23. _____ leather shoes and fashion, Italians are ahead of the field.
A. In favor of B. In terms of C. On behalf of D. In spite of
24. Mr. White is a careful and experienced engineer, so he is often to finish some challenging tasks.
A. appreciated B. approached C. appointed D. agreed
