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
그들은 집단행동을 통해 사회적 변화를 이끌어냈다.geudeul-eun jipdanhaengdong-eul tonghae sahoejeog byeonhwa-reul ikeul-eonaetda.They brought about social change through collective behavior.