问题补充：
Fireworks exploded during opening ceremony of Asian Cup football tournament at Khalifa Stadium．
A. the; a
B. the: the
C. a; a
D. a; the
答案：
(答案→)A. the; a
B. the: the
C. a; a
D. a; the
解析：冠词考查题。“在一次亚冠联赛Khalifa Stadium的开幕式上烟花爆炸了。”第一空特指，用 the；第二空泛指，用a
