----How long does it take us to go to your hometown from here?

----It takes us      hour or more to go to my hometown by       train.

A．an; a

B．a ; an

C．an; /

D．a; /

由经济学家坎托和帕克提出的CP模型用于( )。

A．债项评级
B．市场风险评级
C．操作风险评级
D．国家风险主权评级