第一节：单项填空（共15小题; 每小题1分，满分15分）
21. Hunger is ______ global health risk, which results from ___ poverty.
A. 不填; a B. the; 不填 C. a; the D. a; 不填
22. It's a common __________ for young people to pay a New Year's visit to their elders.
A. sense B. practice C. rule D. scene
