下列属于杀菌剂的抗菌药为（）
A.氨基糖苷类
B.氯霉素类
C.β内酰胺类
D.大环内酯类
E.喹诺酮类
参考答案：A, C, E
Although he knew little about the large amount of work done in the field , he succeeded ____other more well-informed experimenters failed.
A．as
B．unless
C．what
D．where
单折支控/通兑方式管理交易需在（）操作。
A.开户网点
B.二级分行辖内
C.一级分行辖内
D.全国任意网点
