制造滚动轴承应选用()材料。
A.40Cr
B.20CrMnTi
C.GCrl5
D.2Crl3Mo
参考答案:C
I regret ________ that you have failed the exam, but what you should do now is not to regret ______ so
much time but to seize every moment from now on. [ ]
A. to inform; wasting
B. informing; to waste
C. to inform; to waste
D. informing; wasting
工加定位的目的在于确定()的位置,则应根据该基准设计定位方案。
A.设计基准
B.工序基准
C.定位基准
D.装配基准