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问题 单项选择题 B1型题

β2受体激动剂（）

A.激活腺苷环化酶使cAMP形成增加

B.抑制鸟苷环化酶使cGMP形成减少

C.抑制磷酸二酯酶，阻止cAMP衍变成5-AMP

D.抑制旷肾上腺素能受体，阻止ATP分解为ADP

E.稳定肥大细胞膜下列药物的平喘作用是

答案

参考答案：A

解答题

一个平行四边形的底扩大2倍，高缩小2倍，面积不变．______．
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单项选择题

The vast differences in the ways students learn are often_____when they are taught the same thing, in the same way, at the same time. Therefore many of them feel little enthusi astic and even hostile for the ways instruction is handled.

A．disregarded

B．distinguished

C．discharged

D．discerned
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