By the end of last year, another new gymnasium in Beijing.
A. would be pleted
B. was being pleted
C. has been pleted
D. had been pleted
网友回答
A. would be pleted
B. was being pleted
C. has been pleted
(答案→)D. had been pleted
解析：考察时态。By与完成时连用，本题by后面的是过去时的时间状语，故使用过去完成时，故D正确。