刀具在切削中,作用于切削速度方向的分力为最大的分力,占切削力90%左右。
参考答案：对
Sally ______ her homework in the evening. [ ]
A. doesn't
B. doesn't do
C. don't
D. don't do
所有生物的性别都是由X、Y性染色体决定的。
't do