Black Friday: lifetime access is on a special offer in the app, until November 30. Black Friday: special offer on lifetime access, until November 30. Download
수로학은 물의 흐름과 분포를 연구하는 학문입니다.surohak-eun mul-ui heureum-gwa bunpo-reul yeongu-haneun hakmun-imnida.Hydrography is the study of the flow and distribution of water.