Commutative system
[计] 可交换系统
🧩 词语组成解析
a. 交替的, 交换的\\n[法] 交换的, 代替的, 互相的
🗣️ 情景例句
I must prepare my lessons.
我必须准备工课。
A person must strain one's ears to hear a wild animal in the forest.
在森林里，人类必须对野兽竖起耳朵才行。
I spent the whole day in my room, but I did not write a single card!
我在房间里关了整整一天。然而竟连一张明信片也没写成！