问题
单项选择题
氨基糖苷类抗菌药物的主要耐药机制是（）。
A．核糖体50S亚基改变
B．细胞膜摄入减少；产生氯霉素乙酰转移酶
C．药物外排速度加快，核糖体30S亚基改D变；产生灭活酶
D．细胞膜通透性减少；产生钝化酶；核糖体30S亚基蛋白改变
E．细胞膜通透性降低；与PBPs亲和力与结合量降低；产生β-内酰胺酶
答案
参考答案：D
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氨基糖苷类抗菌药物的主要耐药机制是（）。
A．核糖体50S亚基改变
B．细胞膜摄入减少；产生氯霉素乙酰转移酶
C．药物外排速度加快，核糖体30S亚基改D变；产生灭活酶
D．细胞膜通透性减少；产生钝化酶；核糖体30S亚基蛋白改变
E．细胞膜通透性降低；与PBPs亲和力与结合量降低；产生β-内酰胺酶
参考答案：D
I’ve loved my mother’s desk since I was just tall enough to see above the top of it as mother sat doing letters. Standing by her chair, looking at the ink bottle, pen, and white paper, I decided that the act of 1 must be the most 2 thing in the world. Years later, during her final illness, mother 3 different things for my sister and brother. “But the 4 ”, she said, “is for Elizabeth”. I never saw her angry, and never saw her cry. I knew she 5 me, she showed it in action. But 6 a young girl, I wanted heart-to-heart talks 7 mother and daughter. They never happened. And a gulf (深渊) opened between us. I was “too emotional”. 8 she lived “on the surface”. As years passed and I graduated from college, I loved my mother and I wrote to her in 9 words and asked her to let me know in any way she chose that she did 10 me. I posted the letter and waited for her answer. 11 came. My hope turned to 12 , then little interest, finally, peace --- it seemed that nothing happened. I couldn’t be sure that the 13 had even got to Mother. I only knew that I had written it, and I could 14 trying to make her into someone she was not. Now the 15 of her desk told me, as she’d 16 been able to, that she was 17 that writing was my chosen work. I 18 the desk carefully and found some papers 19 --- a photo of my father and a one-page letter, folded and refolded many times. “Give me an answer”, my letter asks, “in any way you chose”. Mother, you always chose the 20 that speaks louder than words.
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