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
비행기의 속도를 측정하기 위해 피토관을 사용합니다.bihaenggiui sogdoreul cheugjeonghagi wihae pitogwaneul sayonghamnida.A pitot tube is used to measure the speed of the aircraft.