lǎo / shī / zhèng / zài / gěi / xué / sheng / jiǎng / jiě / gōng / chě / pǔ / de / jī / běn / xiě / fǎ

老师正在给学生讲解工尺谱的基本写法。

The teacher is explaining the basic notation of gongchepu to the students.