No wonder he looks tired! He’s been studying for the exams all week, ____ he’s been working in a bar at night. 

A．while

B．but

C．plus

D．as

最容易产生对企业的控制权问题的融资方式是（）。

A．股权融资

B．债务融资

C．内部融资

D．向金融机构借款