—I can't thank you enough for the gift you sent me.

—________. [ ]

A. With pleasure  

B. No, thanks

C. Please don't say so  

D. My pleasur

慢性支气管炎急性发作的主要原因是：（）

A.劳累

B.呼吸系统感染

C.过敏性反应

D.吸烟

E.药物