Let's talk about lip-singing.
1. Liu Yumei -- no lip-singing for sure, she sucked that day (it is said she got voice prob at that time);
2. Guo Li -- lip-singing? Not sure, but I heard the noise of the mic hitting her skirt (several times), most-likely the mic was on during the show;
3. Li Xiaohu -- didn't have any clue whether this guy was lip-singing;
Who else, welcome further discussion.