某二价金属A与稀硝酸反应时,A与被还原的硝酸的物质的量之比为2:1,则硝酸被还原的产物是( )
A.NO2
B.NO
C.N2O
D.N2
答案:C
5.―Have you handed in your schoolwork yet?
―Yes,I have. I guess it ____ now.
A.has graded
B.is graded
C.is being graded
D.is grading
以车辆制造业为例,说明供应商一体化的特点。