The new suspension bridge by the end of last month.
A. has been designed
B. had been designed
C. was designed
D. would be designed
网友回答
A. has been designed
(答案→)B. had been designed
C. was designed
D. would be designed
解析：考查时态。根据时间状语by the end of last month.到上个月末可知，用过去完成时，主语The new suspension bridge与动词design为被动关系，故选B。