I am very surprised that even an expert on foreign affairs can know the painting is forgery. （）he can tell who painted it.

A.However

B.Otherwise

C.Nevertheless

D.Moreover

评估大中型网络的核心骨干(主干)交换机性能时，通常最关心的指标是______，与该参数密切相关的参数或项目是______。

A．CPU主频及Flash容量
B．背板交换速度
C．端口类型及数据率
D．扩展槽数量