磁盘冗余阵列技术的主要目的是为了 （44） 。

A．提高磁盘存储容量

B．提高磁盘容错能力

C．提高磁盘访问速度

D．提高存储系统的可扩展能力

We don’t have much homework now and our school-bags are _____ they used to be.   [ ]

A. as heavy as

B. as heavily as

C. not as heavily as  

D. not so heavy as