II. 单项填空（共20小题；每小题0.5分，满分10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，并在答题纸上将该选项标号涂黑。
21. We have every reason to believe that ______ 2010 World Expo in Shanghai will be ______ success.
A. /; a B. the; / C. the; a D. a; a
22. At times, worrying is a normal ______ to a difficult event or situation---a loved one being ______ in an accident, for example.
A. response; injured B. reaction; wounded C. reply; hurt D. reflection; died
23. On October 1st every year all the Chinese people hold great parties ______ the birthday of New China.
A. in celebration of B. in memory of C. in favor of D. in praise of
24.Judging from his ______ look, he has found the key to ______ the difficult problem.
A. excited, solving B. excited, solve C. exciting, solving D. exciting, solve
