zài / jǐ hé / kè / shàng / lǎo shī / jiāo / wǒ men / rú hé / huà / yí gè / zhèng / shí jiǎo xíng

在几何课上，老师教我们如何画一个正十角形。

In geometry class, the teacher taught us how to draw a regular decagon.