下列抗菌药口服后不易吸收（）
A．多西环素
B．青霉素
C．异烟肼
D．阿莫西林
E．氧氟沙星
参考答案：B
下列有关物质应用的说法不正确的是
A．氯气用于制备漂白粉
B．单质硅用于制造光导纤维
C．硫酸铵用于蛋白质盐析
D．三氧化二铁用于生产红色颜料
Cultured pearl is formed by ______.
A．insertion of a pearl into a live mollusk
B．an oyster into which a piece of grit has been placed
C．putting in a live mollusk
D．placing a bead into culture
