问题
选择题
In manufacturing, cheaper materials are constantly being for the better, more expensive kind.
A．maintained
B．cancelled
C．substituted
D．deposited
答案
答案：C
题目分析：A. maintained维持，B. cancelled取消， C. substituted替换，D. deposited储蓄，寄存，放置，安置，句意：在生产中，便宜的材料被不断的替换成更好的，更贵的品种。所以选C。