Good technique in medicine means less pain and fewer deaths and, _____, it's our duty to master it. [ ]

A. naturally

B. therefore

C. particularly

D. similarly

慢性肺心病的病因按原发病的不同部位，可分为（）

A.支气管、肺疾病

B.肺血管疾病

C.肺小动脉炎

D.胸廓运动障碍性疾病

E.脊柱病变