属多肽类，仅对革兰阳性菌有效：
A．琥乙红霉素B．去甲万古霉素C．乙酰螺旋霉素D．依托红霉素E．麦白霉素
参考答案：A
My sister met him at the Grand Theatre yesterday afternoon, so he ________ your lecture. [ ]
A. couldn’t have attended
B. needn’t have attended
C. mustn’t have attended
D. shouldn’t have attended
抬梁式构架
