下列何类药物属抑菌药？（）
A.青霉素类
B.头孢菌素类
C.多粘菌素类
D.氨基糖苷类
E.大环内酯类
参考答案：E
Peter and his brother _____ a great sports collection. [ ]
A. has
B. have
C. to have
D. there are
蓄电池为什么负极板比正极板多一片？
