track conjunction

例句：

1. 1. The train tracks arelined with trees.
   火车轨道两旁种着树。
2. 2. He followed the trail of footprintsto find his lost dog.
   他沿着足迹的踪迹找到了他的丢失的狗。
3. 3. Thescientist used a tracker to follow theanimal's movements.
   科学家用追踪器来跟踪动物的行动。