钻孔时那些因素可能导致孔表面不光滑?
参考答案:
可能的因素有三个:
①钻刃不锋利
②进给量过大
③切削液不足或切削液性能差
—How about singing songs with me?
—I’m sorry I can’t. I help my father with his work. [ ]
A. have to
B. can
C. may
重度营养不良患儿调整饮食,每日开始供给的热量应是()
A.30kcal/kg
B.40kcal/kg
C.50kcal/kg
D.60kcal/kg
E.70kcal/kg