Commutators
(commutator 的复数) n. 换向器, 整流器\\n[化] 对易式; 整流器
🗣️ 情景例句
He gives his harness bells a shake
摇动， 绳上的铃铛
Only three days.
仅三天。
To get a full appreciation of what this means we must turn first to some recent human inventions.
要透彻理解这句话的意义，我们应先回顾一下人类最近的几项发明。