— He didn't go to bed last night until 12 o'clock last night.  

— Yes. He ______ his experiment over and over, working till midnight.  [ ]

A. played        

B. showed    

C. acted      

D. performed  

要实现集成化供应链管理，企业要从自己的利益出发，考虑企业内部的结构优化问题。