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
비행기는 서멀링을 이용하여 높은 고도로 상승할 수 있다.bihaenggineun seomeolling-eul iyonghayeo nopeun godoro sangseunghal su itda.The airplane can ascend to a high altitude using thermaling.