液压卡盘必须处于( )状态，才能启动主轴。
A．工作
B．静止
C．卡紧
D．JOG
参考答案：C
This album is _____ as it was the only one ever signed by the President.
A．unusual
B．unique
C．rare
D．special
调配含有毒性中药饮片处方，每次处方剂量不得超过几日剂量（）
A.1
B.2
C.3
D.4
E.5
