Did the season 7 so you think you can dance dancers, dance with professional dancers
I don't think the season 7 participants in the show danced with professional dancers. It is not documented whether or not any of the participants did perform with professional dancers. Check more details on http://www.starpulse.com/news/Kate_Kostal/2010/08/13/so_you_think_you_can_dance_season_7_f1.
I'm not sure I understand what you are asking here?
Yes one did because her partner had to sit out this round due to a hurt shoulder or elbow.