13:40Snooker: World Championship2011Day 12, Part 1BBC Two Duration: 3 hours, 30 minutes Wed 27th Apr 2011, 13:40 on BBC Two Northern IrelandQuarter-final action continues, with the first two semi-final spots being decided. Matches are the best-of-25 frames.ContributorsPresenter:Hazel IrvineParticipant:Steve DavisParticipant:Ken DohertyParticipant:John ParrottCommentator:Neal FouldsCommentator:Terry GriffithsCommentator:Dennis TaylorCommentator:Willie ThorneCommentator:John VirgoGenresSportSnookerBrandSnooker: World ChampionshipSeriesSnooker: World Championship: 2011 Source: BBC Online