Accounting is described as ________ science of classifying, recording and reporting ________ important financial events.

A．an, the

B．a, 不填

C．不填, 不填

D．不填, the

弗里德曼认为货币需求函数具有的特点是 ( )

A．不稳定

B．不确定

C．相对稳定

D．相对不稳定