tracing stylus

例句：

1. 1. The detective was tracing the movements of a suspect.
   侦探正在追踪嫌疑人的行踪。
2. 2. The artist traced the outline of a flower on paper.
   艺术家在纸上描画了一朵花的轮廓。
3. 3. The scientist traced the movement of the earth's magnetic field.
   科学家追踪地球磁场的运动。