Some of the keys have a special use. There are referred to as command keys. The 3 most common are the Control or (66) , Alternate or (67) 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 (68) need a drive to get information off - or (69) - and put information on the disk - or (70) . 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.
A．read
B．write
C．speak
D．tell
支三叉神经痛。住院、服药，因患者不同意而没作手术。患者面容痛苦，口腔卫生极差。现在仍服用"卡马西平"。检查口腔见左侧上下后牙多个牙有邻面深龋洞，均未治疗，要求医师诊治。