问题补充：
Some teenagers would rather than in their spare time.
A. play computer games, doing exercise
B. to play computer games, to do exercise
C. play computer games, do exercise
D. playing computer games, do exercise
答案：
A. play computer games, doing exercise
B. to play computer games, to do exercise
(答案→)C. play computer games, do exercise
D. playing computer games, do exercise
解析：根据语境可知此题考点是考查固定句型结构would rather do sth than do sth else意思是宁愿做某事而不愿做某事，rather和than的后面都是动词原形。本句的含义是有些青少年宁肯打电脑游戏，也不愿意做运动，根据选择项的提示可知选择A。
