双胍类降糖药最严重的不良反应是
A.胃肠道刺激症状
B.乳酸性酸血症
C.低血糖反应
D.过敏反应
E.畸胎
参考答案:B
--Mary, have you got my email? I sent you a birthday card yesterday.
---Oh, really! I haven't ___my mailbox yet.
A.seen
B.checked
C.received
D.answered