Why so many youths are on playing puter games often puzzles us a lot.
A. fascinated
B. crazy
C. keen
D. fond
网友回答
A. fascinated
B. crazy
(答案→)C. keen
D. fond
解析：考查固定短语。be fascinated by“被......深深吸引”；be crazy about“对......痴迷”；be keen on“喜爱”；be fond of“喜欢”。根据on可知，应该用keen。故选C。