Zài / zhè / mén / kè / shàng / lǎo / shī / yòng / Lí / màn / miàn / jiě / shì / fù / biàn / hán / shù / de / jǐ / hé / xìng / zhì在这门课上,老师用黎曼面解释复变函数的几何性质。In this course, the teacher uses Riemann surfaces to explain the geometric properties of complex functions.