第二部分：英语知识运用（共两节，满分45分）
第一节：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，选出可以填入空白处的最佳选项。
21. Although Zhang Ziyi is _____ international film star, she manages to achieve _____ balance between her career and family.
A. the; a; B. an; a C. 不填；a D. an; 不填
22. The Olympic _____ remind us of where the Olympics are held and the characteristics of the host country.
A. symbols B. signals C. marks D. signs
23. Experts say that the rate at which one ages ______ from person to person and is usually influenced by a number of factors.
A. is varying B. varied C. has varied D. varies
