治疗肺炎球菌肺炎的首选药物是（）
A.磺胺类药物
B.链霉素
C.青霉素
D.庆大霉素
E.四环素
参考答案：C
— My dog's really fat.
— You ________ have given her so much food. [ ]
A. wouldn't
B. can't
C. shouldn't
D. mustn't
细胞代谢所需的O2和所生产的CO2是通过什么渠道跨膜转运
A．脂质双分子层B．载体蛋白C．通道蛋白D．钠泵E．钙泵
