（）是滴丸剂的常用基质.
A.PEG类
B.肥皂类
C.甘油明胶
D.硬脂酸
E.硬脂酸钠
参考答案：A, B, C, D, E
A disk scheduling mechanism in an operating system causes the disk arm to sweepback and forth across the disk surface servicing all requests in its path. This is a
A．First Come First Serve
B．Shortest Seek Time First
C．Scan
D．None of the above
顺丁橡胶外观为（）块状胶。
A.黄褐色
B.黄色
C.无色或浅色
D.灰色
