冷作矫正时,同一处的敲击次数不应超过3-4次,冷作矫正只适用于弯曲量不大于()的曲轴。
A、1-2mm
B、0.3-0.5mm
C、3-4mm
D、0.1mm
参考答案:B
下列说法正确的是 [ ]
A、用明矾可以区别开硬水与软水
B、汽油除去衣服上的油污是“乳化作用”
C、蛋白质与化学肥料碳酸氢铵都含有C、H、O、N元素
D、煤、石油、氢气是三种重要的化石燃料
After retirement, Steven ________ painting, which he had always loved but had not had time for.[ ]
A. left out
B. took up
C. made up
D. picked up