You can hardly imagine the trouble we had _______ in touch with him again?[ ]

A. getting          

B. keeping         

C. to get           

D. kept

鉴别心源性哮喘和支气管哮喘最有意义的是（）

A.端坐呼吸

B.血中BNP含量

C.干湿性啰音的多少

D.夜间呼吸困难

E.是否是受凉感冒后出现