Semigroup
[计] 半群
🗣️ 情景例句
By plane?
坐飞机来？
Harm watch, harm catch.
害人反害己。
When I asked him what he was doing, he smiled guiltily and then put the parcel on the desk.
当我问他正干什么时，他内疚地笑了，然后把那个大包拿到了桌上。