数控代码和刀具模拟切削是由零件轮廓、刀位源文件及工艺参数决定的。
参考答案：对
—Is everyone here today?
—No, Tom isn't here. He must ___________. [ ]
A. is ill
B. be ill
C. be illness
D. healthy
单元机组的控制要解决的主要问题是什么？
