I wonder how you finished the work.

A．I want know how you finished the work.

B．I want to know how you finished the work.

C．I know how you finished the work.

D．I want to know you how finished the work.

广播电视中心设备多采用UPS系统供电，其主要功能包括稳压、外电瞬间断电保护、后备供电和（）。

A．漏电保护

B．滤波

C．负荷平衡

D．配电