1%致死量与99%有效量的比值是指（）
A.效价
B.效能
C.可靠安全系数
D.恢复指数
E.治疗指数
参考答案：C
Could it be in the restaurant ________ you had dinner with me yesterday ________ you lost your handbag?
A．that: which
B．which; that
C．where; that
D．that; where
如果背吃刀量和进给量选得都比较大，选择切削速度时要适当的降低些。( )
