Plano-concave
a. (透镜)平凹的
🧩 词语组成解析
a. （透镜）平的
concave
['kɔn'keiv]
n. 凹面，成凹形;
adj. 凹的;
vt. 使成凹形;
🗣️ 情景例句
Lacks courtesy is ill-mannered.
不礼貌，举止不当。
It's fine once you get used to it.
习惯就好！
The policemen could not cope with the crowds.
警察无法对付群众。