Permutability
換排性, 轉置性, 交換性
? 同義詞
??? 情景例句
Richard, did you go to the aerobics class, really? Richard
你真的上了有氧運動課嗎？
An empty sack cannot stand upright.
空麻袋，立不直。
That's it. Thank you for your help. Goodby.
對的。謝謝你的幫忙，再見。