I had never expected _____ such a big audience there.

A．it to be

B．there being

C．there to be

D．there to have

隔离开关的交流耐压试验，通常只在安装或更换新的（）时进行。

A.绝缘子或主绝缘杆

B.导电带

C.动、静触头

D.机构配件