22. ---Can we meet at 3 o’clock tomorrow afternoon?

--- That doesn’t suit me. I’m afraid I _____________.

A．will be working

B．will work

C．am going to work

D．am about to work

UPS有螺旋型和静止型之分，螺旋型采用电动发电机组，现在较普遍采用静止型UPS。静止型UPS由整流器、蓄电池组、逆变器和（）等部件组成。

A、静态电子开关

B、动态电子开关

C、过载保护开关

D、稳态保护开关