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
어두운 곳에서 시력을 잃지 않기 위해서는 암순응의 상태가 필요하다.eoduun goseseo sireogeul ilhji anki wihayeoseun amsun-eung-ui sangtaega piryohada.To avoid losing vision in a dark place, a dark adapted state is necessary.