ok, major mistakes: (and my corrections probably have some mistakes in them as well, this isn't easy stuff) 1. "Its" versus "It's". Its is possesive. It's mean

ok, major mistakes: (and my corrections probably have some mistakes in them as well, this isn't easy stuff) 1. "Its" versus "It's". Its is possesive. It's means "it is". 2. "game-changing device with graphical user interface." should be "a game-changing device with a graphical user interface." Notice the "a". 3. "but it’s competitors" - you mean this: "by its competitors". Notice the BUT and the ITS. 4. "they offered cheaper version of Mac also with graphical user interface" should be: "they offered a cheaper version of the Mac which had the same graphical user interface". That's just the first paragraph :) But writing is hard, especially if it's not your native language, so don't give up.