Qacs
(qac 的复数) abbr. quaternary ammonium compound 季铵化合物（杀菌剂）
🗣️ 情景例句
It all sounds so easy.
一切听起来竟是如此简单。
Oh? Where were you?
哦，上哪儿去了？
Is that an English car?
那是辆英国产的小汽车吗？