put in the Google Engage in textbooks application for Android and iPad/apple iphone. It syncs immediately together with your account and means that you can study on-line or offline where ever you're. ?? ????? ??? ?????? ?????? ??????? ?????? ? ?? ???? ?? ???? ?????? ??? ????? ?????? ????? ?? ???? ?????? ????? ???? ??????? ????? ????? ???? ??????