We went through a period_______ communications were very difficult in the countryside.

A．which

B．in which

C．whose

D．with which

凡是在高压设备上或在其他电气回路上工作需要将高压设备停电或装设遮拦的，均填写（）。

A、第一种工作票

B、第二种工作票

C、第一种操作票

D、第二种操作票