—Nice to see you again after all these years. What _____?

—Well, I’ve tried many things since we left school. I’m now working for a large oil company.

A．have you done

B．were you doing

C．did you do

D．have you been doing

通过设备、材料、配件等生产消耗（）关系形成内部物资市场。

A.管理

B.使用

C.供求

D.考核