Concavities
n. 凹面, 成凹形( concavity的名词复数 )
🗣️ 情景例句
I'll try to explain.
我会尽量给你解释。
A secret between more than two is no secret.
两人以上知道的秘密就不算秘密。
We want it to stay down the hole until we can lead it off in a controlled manner.
我们要让石油留在井下，直到我们能用一种有控制的方法把它引上来为止。