track dolly

例句：

1. 1. The train tracks are lined with trees.
   火车轨道两旁种满了树。
2. 2. He followed the trail of footprints to find his lost dog.
   他沿着脚印找到了他的丢失的狗。
3. 3. The scientist used a track locator to map the underground cave network.
   科学家使用一个测距仪来绘制地下洞穴网络图。