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
현측계류판은 수로의 흐름을 조절하는 데 사용됩니다.Hyeoncheuggyeryupan-eun suroui heureumeul jojeolhaneun de sayongdoemnida.The channel plate is used to regulate the flow of water.