22．The purpose of their explorations is as important to them as____to us.

A．they are

B．they have

C．it is

D．it has

变压器的额定容量是指变压器额定运行时（）。

A、输入的视在功率

B、输出的视在功率

C、输入的有功功率

D、输出的有功功率