问题补充:
On April 24, Tsinghua University its 100th anniversary at the Great Hall of the People in Beijing.
A. congratulated
B. challenged
C. celebrated
D. participated
答案:
A. congratulated
B. challenged
(答案→)C. celebrated
D. participated
解析:四个选项分别表示向某人祝贺、挑战、庆祝(大型活动)和参加(某事),根据题意选C,四月二十四日,清华大学在北京人民大会堂庆祝了它的100周年纪念日。