Qacs
(qac 的复数) abbr. quaternary ammonium compound 季铵化合物（杀菌剂）
🗣️ 情景例句
I think Michelle is better off staying where she is.
我觉得Michelle待在原地比较好。
What are those?
那些是什么？
It's no use complaining.
发牢骚没什么用。