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 테일콘은 안정성을 높이는 데 중요한 역할을 합니다.bihaenggiui teilk'on-eun anjeongseong-eul nopineun de jungyohan yeoghal-eul hamnida.The tail cone of the airplane plays an important role in enhancing stability.