Heptaoxacycloheneicosane
[化] 七氧代环二十一烷; 21-冠-7; 21-冠醚-7
🗣️ 情景例句
Sounds like Richard.
听起来跟Richard一样。
Deliver not your words by number but by weight.
言不在多，而在有物。
I insist that you give me my money back.
我要求你把钱退给我。