The lady _________ dancing as a hobby in her sixties, and she is really good at it now.

A．dressed up

B．looked up

C．took up

D．put up

以下哪些关于RAID1的描述是正确的（）

A、速度慢，安全性高

B、速度快，安全性差

C、速度慢，容量利用率高

D、安全性差，容量利用率低