Tracer elements
[医] 示踪元素
🧩 词语组成解析
tracer
['treisə]
n. 追踪者，描图者，（铁笔等）绘图工具;
n. 原理, 基础
🗣️ 情景例句
You're the only one
你是我们当中唯一
A fool can ask more questions than seven wise men can answer.
一愚发问，七智结舌。
That's not allowed. Once you are in here, listen to your teacher.
那是不允许的。一旦进来了，你们要听老师的话。