嵌体洞各轴壁要求()
A.各轴壁平行或向面外展2~5°
B.各轴壁平行或向面内收2~5°
C.底部制备倒凹以利固位
D.各轴壁形成的线角应圆滑
E.轴壁与底形成的线角应圆滑
参考答案:A
已知集合M={1,2,3,m},N={4,7,n4,n2+3n}(m、n∈N),映射f:y→3x+1是从M到N的一个函数,则m-n的值为( )
A.2
B.3
C.4
D.5
There aren't _______ vegetables at home now. Can you go and get _______? [ ]
A. some; some
B. any; any
C. some; any
D. any; some