T3和T4合成的起始物为()
A.甲状腺素
B.反向T3
C.酪氨酸
D.碘
E.活化碘
参考答案:C
解析:T3和T4均为酪氨酸含碘衍生物。
With many major economic problems________ to be solved, there is no point predicting the growth rate of this year now.
A.remaining
B.remained
C.have remained
D.having remained
在经济全球化进程中,随着空间经济活动的变化,城镇体系的结构呈:
A.网络结构
B.层次结构
C.水平结构
D.垂直结构