back pitch

• 后节距,背景距

back pitch的用法和样例：

例句

1. Convolutions frequently alternate in direction of rotation and vary in pitch.
   盘旋经常改变回转方向和节距。
2. The straightening effect of straightener can be improved along with the change of pitch.
   采用改变节距的方法，提高矫直机的矫直质量。