机床主轴箱主轴孔的精加工方法有()。
A.精镗一珩磨
B.精镗一浮动镗
C.精镗一金刚镗
D.金刚镗一珩磨
E.精镗一滚压
F.金刚镗一滚压
参考答案:B, D, F
— You haven’t said a word about my new coua, Brenda. Do you like it ?
— I’m sorry, I _____ anything about it sooner. I certainly think it’s pretty on you.
A.wasn’t saying
B.don’t say
C.won’t say
D.didn’t say
对于空中航空器来说,(),则尾流越强。
A.重量越大,速度越高
B.重量越大,速度越低
C.翼展越长,速度越低
D.翼展越长,速度越大