Two years ago I broke my arm football.
A. when playing
B. while played
C. played
D. having played
网友回答
(答案→)A. when playing
B. while played
C. played
D. having played
解析：整个句子已经有谓语动词broke，再出现谓语动词必须用连词，when 后的句子补充完整应是：when I was playing；因为I与play是主动关系，所以排除B，故选A。