刮研后的滑销应达到什么要求?
参考答案:
要保证在其长度方向上间隙均匀,符合质量标准,滑动面的光洁度要不低于▽6,接触面积在80%以上。
Teachers often tell us in the river after school.
A. don’t swim B. not swim C. not to swim