案例分析题Some of the keys have a special use. There are referred to as command keys. The 3 most common are the Control or （） , Alternate or （） and the Shift keys though there can be more (the Windows key for example or the Command key). Each key on a standard keyboard has one or two characters. Press the key to get the lower character and hold Shift to get the upper. Disk Drives - All （） need a drive to get information off - or （） - and put information on the disk - or （） . Each drive is designed for a specific type of disk whether it is a CD, DVD, hard disk or floppy. Often the term ’disk’and ’drive’are used to describe the same thing but it helps to understand that the disk is the storage device which contains computer files-or software - and the drive is the mechanism that runs the disk. on the disk - or （）

A. read
B. write
C. draw
D. fill