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
석탄수송철도는 석탄을 효율적으로 운송하는 데 필수적입니다.seoktan susong cheoldo-neun seoktan-eul hyoyuljeogeuro unsonghaneun de pil-su-jeog-imnida.The coal transport railway is essential for efficiently transporting coal.