患者男性，48岁。反复发作性喘憋8年，加重1周，夜间不能平卧。入院后查体：双肺散在哮鸣音，呼吸30次／分。既往有甲亢病史。入院后给予氨茶碱和沙丁胺醇（舒喘灵）等治疗。
关于沙丁胺醇（舒喘灵）的平喘作用原理，下列哪项是错误的（）.
A.主要刺激β2-肾上腺素能受体
B.激活腺苷环化酶
C.阻止cAMP衍变成5-AMP
D.与氨茶碱合用有协同作
参考答案：C
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| My father enjoys bike riding.Ever since I was little, I've always loved going biking with my dad.__1__, as I became a teenager, other thins began to draw my__2__.Suddenly, it was important to do things with __3__.I saw my dad every evening at home.Why did I have to__4__my Sundays to allday bike trips with him, too?If my indifference (冷漠) hurt him, my father kept__5__, but he would always let me know when he was planning a bike trip__6__I wanted to come. It was a Sunday morning, and I was in low__7__.Two of my friends had gone to the movies without inviting me.Just then my father__8__my room." It's a beautiful day.Want to go for a__9__, today, Beck?""Leave me alone!"I impatiently__10__. Those were the las  t words I said to him before he left the house that__11__.Several hours later, the police called us, __12__us that Dad had a traffic accident.My father's injuries were serious.It took several days before he could__13__speak.Beside his bed I eldhishandgently__14__ of hurting him. "Daddy...I'm sorry...""It's okay, sweetheart.I'll be okay." "No, " I said, "I__15__what I said to you that day.You know, that morning?" "Sweetheart, I don't__16__anything about that day.I remember kissing you goodnight the night before, though." He__17__a weak smile. I felt regretful for my thoughtless remark, for I__18__, wanted him to leave me alone.My teacher once told me that__19__have immeasurable power.They can hurt or they ca  n heal.And we all have the__20__to choose our words.I intend to do that very carefully from now on. | ||||
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