药物中所含杂质的最大允许量叫做
A．检测限
B．杂质限量
C．定量限
D．许可值
E．规定限量
参考答案：B
Between the two periods of classes is a break, _______ we can have a short rest.
A．then
B．where
C．when
D．which
试述沙眼的防治。
