zài / jǐ hé / kè shàng / lǎo shī / ràng / wǒ men / zhèng míng / zhēng xíng / de / miàn jī / gōng shì

在几何课上，老师让我们证明筝形的面积公式。

In geometry class, the teacher asked us to prove the area formula of a kite.