机床热变形包括(           )
A、主轴箱温升
B、立柱倾斜
C、导轨凸起
D、主轴速度增加

A．The molecules in the two cylinders also have the same average speeds.
B．The average kinetic energy of the nitrogen molecules is less than the average kinetic energy of the oxygen molecules.
C．The temperature of cylinder B is greater than the temperature of cylinder A.
D．The two gases have different temperatures.

A．正确
B．错误