track mark

例句：

1. 1. The policeare still investigating the mysterious disappearance ofthe missing person.
   警方仍在调查失踪人员的神秘消失事件。
2. 2. The hikers found atrack mark in the forest, leading themto believe they had been followed.
   徒步旅行者在森林中发现了一条踪迹，使他们相信有人跟踪了他们。
3. 3. Thescientist used a microscope totrace the chemical composition of thesample.
   科学家使用显微镜来追踪样本的化学成分。