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
사람의 귀에는 세 개의 작은 뼈가 있는데, 그 중 하나가 등골이다.saram-ui gwie-neun se gae-ui jag-eun ppye-ga itneunde, geu jung hanaga deunggol-ida.In the human ear, there are three small bones, one of which is the stapes.