shù / xué / lǎo / shī / huà / le / liǎng / gè / tóng / xīn / yuán / lái / jiě / shì / jǐ / hé / gài / niàn / 。

数学老师画了两个同心圆来解释几何概念。

The math teacher drew two concentric circles to explain a geometry concept.