【单选题】对于只作膨胀功的封闭体系,系统内能变化的值是: ( )
【单选题】When the child begins to suffer the consequences of his early mistakes, we should ______.
A.
help him correct the mistakes
B.
punish him for the wrongdoing
C.
leave him alone to work out the problem
D.
teach ourselves to understand their mistakes
【简答题】机床的主要技术参数包括尺寸参数、运动参数和()参数。
【简答题】()是描述磁场内某点磁场强弱和方向的物理量。
【简答题】机床的主要技术参数包括主参数、尺寸参数、(__)、(__)。
【简答题】机床的主要技术参数包括( )、( )、( )、( )。