You must apologize ______ her ______ what you have done.

A．/; for

B．for; to

C．to; /

D．to; for

真空断路器出线侧安装避雷器的作用是（）。

A.防止电弧重燃

B.有利于熄灭电弧

C.限制操作过电压

D.防雷