By the end of the last month, I all the CDs Of Justin Bieber.
A. collect
B. collected
C. have collected
D. had collected
网友回答
A. collect
B. collected
C. have collected
(答案→)D. had collected
解析：这题考查时态：By the end of +过去时间，就用的是过去完成时，这是固定用法
句意是：到这月底为止，我已经收集所有Justin Bieber.的CD了选D。