水泥环上端至补心上平面的距离称()。
A、套管深度
B、油管深度
C、水泥帽
D、水泥返高
参考答案:D
—Do you think yesterday's math problem was difficult?
—Yes. I could _____ work it out. [ ]
A. hardly
B. finally
C. already
D. easily
16V280柴油机3310kW运转时,最高爆发压力为()。
A、2.65MPa
B、2.95MPa
C、13.24MPa
D、17.1MPa