Concave polygon
n. 凹多边形
🧩 词语组成解析
concave
['kɔn'keiv]
n. 凹面，成凹形;
adj. 凹的;
vt. 使成凹形;
polygon
['pɔligən]
n. 多边形，多角形;龟裂状;
🗣️ 情景例句
Well,
好啦，
Laugh before breakfast you'll cry before supper.
乐极生悲。
When a student recently saw two workmen using a pneumatic drill outside his university, he immediately telephoned the police and informed them that two students dressed up as workmen were tearing up the road with a pneumatic drill.
最近有个学生看见两个工人在学校门外用风钻干活，马上打电话报告警察，说有两个学生装扮成工人，正在用风钻破坏路面。