链霉素分子中含有的结构为（）。
A.绛红糖胺
B.链霉胍
C.酚羟基
D.氢化噻唑环
E.氢化噻嗪环
参考答案：B
Mary writes __________ than __________ boy in her class.
A．more careful; the other
B．more carefully; any other
C．more carefully; the other
D．more carefully; any
请论述如何对鸡蛋的损耗进行控管？
