问题补充：
The construction of the two new railway lines by now.
A. have been completed
B. has been completed
C. has completed
D. have completed
答案：
A. have been completed
(答案→)B. has been completed
C. has completed
D. have completed
解析：考查时态及语态，根据题中的时间by now，应用现在完成时态，句意：到现在为止两条新铁路线的建造已经被完成了。根据语境应用被动语态，所以选B。
