—Would you like to go to the shopping mall with me tonight?

—I’d like to, but I have to attend a lecture _______ in the school library.

A．given

B．being given

C．having been given

D．to be given

当发电机输出电压高于蓄电池电压，一般发电机的转速达到1000r/min左右时，励磁电流便由发电机自身供给，这种励磁方式称为（）。