Concavoconcave
[医] 对凹的, 双凹的
🗣️ 情景例句
Good-bye, Dean Rafer.
再见， Rafer主任。
One ploughs, another sow; who will reap no one knows.
有的耕，有的播，谁来收获很难说。
It was not long before a helicopter arrived on the scene to rescue the survivors of the plane crash.
不久，一架直升飞机飞抵飞机失事现场，来搭救这几个幸存者。