Do you know a concert _____ in our hometown next month?

A．will be held

B．is going to be held

C．is to be held

D．all A, B, C

高压断路器、负荷开关校验的项目包括( )。

A．额定电压

B．额定电流

C．额定开断电流

D．环境条件

E．短路电流动稳定、热稳定