【简答题】A.At about 4: 30 B.At about 5: 15 C.At about 6: 30 D.At about 8: 00
【单选题】When is the birthday party having?
【简答题】A.At about 4:30. B.At about 5: 15. C.At about 6:30. D.At about 8:00.
【简答题】用展成法加工齿轮时,有时会出现刀具的顶部切入齿根,将齿根部分渐开线齿廓切去的现象称之为 [填空(1)] 。A. 根切