在胃酸中稳定且无味的抗生素是
A．红霉素B．琥乙红霉素C．克拉霉素D．阿齐霉素E．罗红霉素
参考答案：B
It's eight o'clock. The students ______ an English class. [ ]
A. have
B. having
C. is having
D. are having
谷类食品保留哪部分容易引起食物的变质（）
A.胚
B.胚乳
C.谷皮
D.吸收层
E.糊粉层
