Tracer composition
[化] 曳迹剂
🧩 词语组成解析
tracer
['treisə]
n. 追踪者，描图者，（铁笔等）绘图工具;
🗣️ 情景例句
Rock-a-bye, baby, on the tree top,
摇呀摇， 小宝宝， 在树梢，
Every man has the defects of his qualities.
一个人的好品质上也有不足之处。
You can never turn the clock back.
时光不能倒流。