Zhengzhou Subway Line 1 which is 26.2 kilometers long into trial operation (试运营) on December 26th, 2013. It has eased (缓解) the traffic pressure greatly.
- A.put
- B.was put
- C.will put
- D.is put
答案
正确答案:B
知识点:被动语态 动词时态:一般过去时

根据语境可知地铁是被投入试运营的,所以要用被动语态;由时间状语“on December 26th, 2013”可知时态应为一般过去时。所以答案选B。

略
