问题补充:
The old city wall in the Ming Dynasty.
A. was been built
B. has been built
C. was built
D. had been built
答案:
A. was been built
B. has been built
(答案→)C. was built
D. had been built
解析:考查时态和语态。句意“那些老城墙建于明朝。”根据句意可知,应该用一般过去时,wall和build之间是动宾关系,用被动语态。故选C。