kilometers of track operated

例句：

1. 1.The distance between the two cities is approximately 500 kilometers.
   两座城市之间的距离大约是500公里。
2. 2.He walked for miles to reach his destination.
   他走了好几个小时才到达目的地。
3. 3. The marathon race covers a total of 42 kilometers.
   马拉松赛跑全程42公里。