小鼠的妊娠期为()天。
A.19-21
B.29-31
C.9-10
D.39-41
参考答案:A
You often have bread for breakfast, ____ you?[ ]
A. don't
B. haven't
C. aren't
D. will
镜检 * * 分泌物见到线索细胞,可诊断为细菌性 * * 病。