临界变形量
参考答案：加热到再结晶温度以上时能使金属材料发生再结晶的最小预变形量。
机械密封中弹性元件有()和()两种。
Car seatbelts save lives. Every driver should wear________to ensure their safety. [ ]
A. this
B. it
C. that
D. one
