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
Even though they are not doubtful at all _______ John will pass the exam, I still wonder ______ he is fully prepared.
A．whether; that
B．that; whether
C．that; that
D．whether; whether
酸性废水的中和方法有哪些？
