If the computer is _______ good as you said,  we shall consider ______ one.

A．much ; buying

B．still ; to buy

C．that ; buying

D．too; buy

背靠背直流输电系统的主要特点是直流侧可以选择（）。

A.高电压大电流

B.低电压低电流

C.高电压低电流

D.低电压大电流