在自然数范围内,方程3x+y=10的解是 _______.
用x的代数式表示y，则，故x可取0,1,2,3
-Got your driving license?
-No. I ___ too busy to have enough practice, so I didn’t take the driving test last week. I am going to next
week. [ ]
A.was
B.have been
C.am
D.had been
巡检压缩机时发现离心式压缩机轴振动大，应如何处理？
，故x可取0,1,2,3
，故x可取0,1,2,3