Recently, much more emphasis has been put _____ developing the students' creativity. [ ]

A. onto

B. in

C. over

D. on

男性，55岁。3年来经常反复咯血和咳黏稠痰，低热，较前消瘦，活动后感气短，乏力，胸片左上肺有片状及条索状阴影，其中并有透光区，胸廓下陷，气管左移。

下一步最重要的检查是

A．胸部CT

B．肺功能测定

C．痰细菌培养+药敏

D．痰找结核菌