trac·er
noun/ˈtreɪsə(r)/
/ˈtreɪsər/
- a bullet or shell (= a kind of bomb) that leaves a line of smoke or flame behind it
曳光弹 - tracer bullets
曳光弹。
- tracer bullets
- (specialist) a radioactive substance that can be seen in the human body and is used to find out what is happening inside the body
示踪剂 - Radioactive tracers have been used to map the metabolic activity of the brain.
放射性示踪剂已被用来绘制大脑的代谢活动图。
- Radioactive tracers have been used to map the metabolic activity of the brain.