—Did your sisters go to the concert last night?

—No, we               went to my aunt's birthday party.

A．both

B．all

C．either

D．none

严禁在接触网（）并采取安全措施的情况下，攀登机车、车辆顶部或站在货物上作业。

A.未停电、接地

B.未停电

C.未接地

D.停电