问题补充：
The top officer in Beijing says that all construction work for the Beijing Olympic
by .
A. has been completed
B. has been completed
C. will have been completed
D. will have completed
答案：
A. has been completed
B. has been completed
(答案→)C. will have been completed
D. will have completed
解析：句子主语all construction work和 complete构成动宾关系，所以要用被动语态；再者，“by+将来时间”作状语时，句子要用将来完成时态。
