不具有生物活性的药物是（）
A.木脂素
B.黄酮
C.蒽醌
D.生物碱
E.肽类
参考答案：A, B, C, D
—"It's too cold. Would you mind _______ the window?"
—"_______. But don't do it now." [ ]
A. to close; Sure
B. closing; Good idea
C. closing; Better not
D. closing; Of course not
光缆按结构不同可分为哪些常见种类？
