—I’m not sure when the 6th national population census(人口普查)completed?— November .A. O

问题补充：

—I’m not sure when the 6th national population census(人口普查)completed?

— November, .

A. On

B. In

C. At

D. Of

答案：

A. On

(答案→)B. In

C. At

D. Of

解析：考查点：介词辨析。解题思路：在某年用介词in.