小儿碘缺乏症的根本原因是（）
A.早产
B.食物和饮水中缺碘
C.甲状腺机能低下
D.孕母日照时间不足
E.生长过快
参考答案：B
—Your spoken English is much better.
—Thank you. My teacher often asks us ______ English as ______ as possible. [ ]
A. to speak; much
C. to speak; many
B. not to speak; much
D. not to speak; more
以下给出的地址中，属于子网197.182.15.19/28的主机地址是______。
A．197.182.15.17 B．197.182.15.14C．197.182.15.16 D．197.182.15.31
