Concavities
n. 凹面, 成凹形( concavity的名词复数 )
🗣️ 情景例句
Bye.
再见。
Take care of yourself and don't forget to keep in touch.
多多保重。别忘了保持联系。
What about your bag? Would you like me to carry it?
手提包呢？您要我提吗？