《铁路工务安全规则》规定，施工中，Ⅰ级施工可以影响接触网支柱、地锚等设施的稳定。
参考答案：错
— How old is the bridge over there?
— Oh, it's very old. It _____ about eight hundred years ago. [ ]
A. has built
B. is built
C. was building
D. was built
（）。
（）。