— Are you still going to Shanghai for the Spring Festival?

— Yes, but I really _____ because I have a lot of things to deal with.

A．can’t

B．mustn’t

C．won’t

D．shouldn’t

110kV（或220kV）馈电线，其电源侧距离保护的振荡闭锁（）.

A、退出运行

B、必须启用

C、改定值后可不退

D、以上说法都不对