As an English major student , I think business English is more practical than other fields.

A．a English student / field

B．a English major student / regions

C．an English major / courses

D．an English student major /sciences

RAID级别是指磁盘阵列中硬盘的组合方式，不同级别的RAID为用户提供的磁盘阵列在性能上和安全性的表现上也有不同。以下 (31) 是具有磁盘镜像和双工功能的磁盘阵列。

A．RAID 1

B．RAID 5

C．RAID 7

D．RAID 10