lǎo / shī / zhèng / zài / gěi / wǒ / men / jiǎng / diū / fān / tú / fāng / chéng / de / jī / běn / gài / niàn老师正在给我们讲丢番图方程的基本概念。The teacher is explaining the basic concepts of Diophantine equations to us.