Prime (2005, USA) C-105m. ** D: Ben Younger. Starring Meryl Streep, Uma Thurman, Bryan Greenberg, Jon Abrahams. Slightly sub-standard romantic comedy about recently divorced 37-year-old Thurman and her infatuation with 23-year-old Greenberg. The hitch: He's her therapist's son! One-joke comedy tries to be authentic but fails because there are only occasional smiles instead of the laughs in this contrived story. Thurman and Streep are appealing, though. Written by the director.