spacing track

例句：

1. 1. The book has a spacing of 20 pages between each chapter.
   这本书每章之间有20页的间隔。
2. 2. The teacher asked the students to space their desks evenly.
   老师要求学生们把桌子摆得均匀间隔。
3. 3.The distance between the two cities is about 500 kilometers.
   这两个城市之间的距离大约是500公里。