second interview

I recently got a second interview call from bhc Chennai
To attend on 29th of April I'm worried what possible questions can be asked.and how long would it be, is there a possible rejection . . This is the first time I've applied abroad .and moreover I was called on 29th while my course starts at 28th and they asked me to get an extension of the Cas from the university .. dnt knw y they called me a day after the cousrse start date . Or it should have been an unclear intervw that I have given before through Skype or my gap of two years between my education . Pls help