Since the opening and reform policy, China a boom in its economy.
A. enjoys
B. has been enjoying
C. enjoyed
D. having enjoyed
网友回答
A. enjoys
(答案→)B. has been enjoying
C. enjoyed
D. having enjoyed
解析：考查时态。句意：自从改革开放政策以来，中国一直经济繁荣。用现在完成进行时态表示的是从过去到现在还要持续下去。根据题意中国的经济还要繁荣下去。故选B。