Concave line
[计] 凹线
🧩 词语组成解析
concave
['kɔn'keiv]
n. 凹面，成凹形;
adj. 凹的;
vt. 使成凹形;
line
[laɪn]
n. 线条;排;行列;界线;
vt. 排队;用线标出;沿…排列成行;给…安衬里;
vi. 形成一层;排队;击出平直球;
🗣️ 情景例句
Lacks courtesy is ill-mannered.
不礼貌，举止不当。
What have you done?
你究竟都做了些什么？
Last summer, I went to Italy.
去年夏天，我去了意大利。