Complex sentence: Rotten Tomatoes gives the film a "certified fresh" score of 98% based on 251 reviews, with a weighted mean score of 8.5 out of 10, the second highest-rated film in 2009, right behind Pixar's "Up".
Split into simpler sentences: Rotten Tomatoes gives the film a rating of 98%, based on 251 reviews, with a weighted mean rating of 8.5/10. It was the second highest-rated film of 2009, behind Pixar's "Up".