Tracer technique
[化] 示踪技术
🧩 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
We needed the money.
我们当时需要钱。
How long have you stayed there?
你在那儿住多久了？
'At what time did you arrive at the station?'
“您几点钟到的火车站？”