速效抑菌药是（）
A．青霉素类
B．四环素类
C．氨基糖苷类
D．多黏菌素类
E．磺胺类
参考答案：B
—We must act now because time is _______.
—Yes. Let’s start.
A．coming out
B．giving out
C．cutting out
D．running out
英译中：Channel of distribution
