男性，60岁。咳嗽3个月伴痰m，近1个月来进行性气急来院就诊。仰卧位时气急加重。体检：吸气性呼吸困难，见三凹征，两肺闻及喘鸣音。常规X线胸片未见明显异常。其诊断首先应考虑（）。

A.喉结核

B.急性喉炎

C.支气管哮喘

D.气管肿瘤

E.气管异物

The constitution, unlike other forms of laws, is fundamental ______ our social system working properly. [ ]

A. for keeping  

B. to keeping  

C. to keep    

D. with keeping