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问题 单项选择题

增强肾上腺素能药物的β受体激动作用采取的办法是（）。

A.去掉侧链上的羟基

B.去掉苯环上的酚羟基

C.在α-碳上引入甲基

D.在氨基上以异丙基或叔丁基取代

答案

参考答案：D

补全对话，情景问答
补全对话。
A.I'm Wang Lin.
B.Which one do you want?
C.We want to climb Lushan (爬庐山). D.How much is it?
E.I want to buy some tickets.
A: May I help you?
B: Yes, 1.            
A: All right. To where?
B: 2.            So we want to buy the tickets to the nearest station (最近的车站) on Saturday evening.
A: OK. Starts at 10:50P.m.and arrives at 11:00 a.m. to Lushan Railway Station, Jiangxi Province (江西省).
B: That's nice. 3.            
A: 100yuan for the hard seat and 180yuan for the soft seat. 4.            
B: I want the hard seat.
A: All right. 10 hard seat tickets. And your name?
B: 5.           Thank you!
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单项选择题

旅客误机如要求退票，须支付误机费，一般为客票的（）。

A.10%

B.20%

C.50%

D.30%
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