"It was fortune that paid me a visit ____," said the modest professor at the award ceremony. [ ]

A. by mistake

B. by chance

C. in order

D. in place

企业高层主管人员了解客户期望的主要渠道是______

A．下行沟通
B．水平沟通
C．向上沟通
D．斜面沟通