Nancy hasn’t begun on her PH.D ________ working on her master’s degree.

A. still because she is yet

B yet as a result she is still

C yet because she is still

D still while she is already

下面哪些是CVM的功能（）

A.虚拟机生命周期管理

B.用户自助申请虚拟机

C.虚拟机迁移

D.基于虚拟机的计费