He has some trouble ____ his classmates but he has no trouble ____ doing his lessons. [ ]

A. with; with

B. with; in

C. in; in

D. in; with

男，60岁，吸烟史30年，慢性咳嗽、咳痰12年，气急3年，呈逐渐加重，胸片示肋间隙增宽、双肺透亮度增加，两下肺纹理乱。

提示：患者诉无心脏疾患，无结核病史。提问：为进一步明确诊断，首选以下哪项检查（）

A.纤维支气管镜活检，BALIF

B.胸部CT

C.肺功能

D.痰培养+药敏

E.血常规