—I called you at 5:00 yesterday afternoon, but no one answered.

—Sorry, I with my parents ________ at that time.

A．was shopping

B．were shopping

C．are shopping

D．went shopping

工作票实施（）的管理原则。运行、检修主管部门应是确保工作票正确实施的最终责任部门。安全监督部门是工作票的监督考核部门，对执行全过程进行监督，并对责任部门进行考核。

A、组织措施

B、技术措施

C、施工措施

D、逐级负责

E、分级管理