单项选择题
A. B. C. D.
A.顺铣 B.逆铣 C.顺逆铣 D.二者都不是
A. G90 H02 X70 Y20 R-50 B. G91 G02 X50.0 Y-50.0 R-50.0 C. G90 G02 X70.0 Y20.0 R50.0 D. G91 G02 X50.0 Y-50.0 R50.0