营业成本是指按照会计核算程序计算出来的一定时期内实际耗用的原材料和燃料价值的（）。

A、单位平均数

B、比值

C、总和

D、消耗率

The idea was just beginning to ______ in America and we knew that it was going to become the way that retailing companies were run.

A. show up
B. catch on

C. open out

D. get by