My 6-year-old daughter went to the dentist's nervously, but the smiling doctor put her __ in no time.[      ]

A. with ease

B. in ease

C. at ease    

D. for ease

下列叙述中，错误的是

A．硬盘在主机箱内，它是主机的组成部分

B．硬盘属于外部设备

C．硬盘驱动器既可做输入设备又可做输出设备

D．硬盘与CPU之间不能直接交换数据