If the ordered spare parts have been modified by manufacturer, which of the following should be pay attention to?（）

A.the reason of replacing
B.the course of replacing
C.crews who do this work
D.where and when the replacing being done

A.Cooling water is alkalescence
B.cooling water is acidity
C.cooling water has salinity
D.cooling water has impurity

A.alkale scence
B.acidity
C.salinity
D.impurity