we have seen lots of D4 opening in this tournament !! like semi slav, Grunfiled etc, but is blitch will be D4 or E4 ?, & can we see any Gambit This time ? i m waiting for some gambit ? 

Yes, and he has played 1 e4 and encountered Sicilians from Gelfand three times.  Both he and Gelfand have at least offered pawn sacs, true gambits.

  They don't play "gambit" openings because most of them are objectively inferior and they are playing for the world's title.

today is the last day , let see who will be the champ ?

Not everywhere it is the last day! Over here it is the day before!