Fall Tuning

While the networks premiere 36 new series, their returning shows are adding and dropping characters and tweaking story lines in order to keep audiences interested. Here’s a look at what’s new this fall on some of your favorite shows:

ABC

“Boy Meets World”: Matthew Lawrence (“Brotherly Love”) plays Eric’s college roommate, who also happens to be Shawn’s half-brother. Trina McGee-Davis joins the sitcom in the recurring role of Topanga’s friend. Fridays at 8:30 p.m. Oct. 3.

“The Drew Carey Show”: Drew will be getting upwardly mobile African American neighbors. Wednesdays at 9 p.m., beginning this week.

“The Practice”: Lara Flynn Boyle (“Twin Peaks”) joins David E. Kelley’s law series as an assistant D.A. Already premiered.

“Sabrina, the Teenage Witch”: Martin Mull joins the cast as the new vice principal of Sabrina’s school, and Alimi Ballard plays a male witch who tests Sabrina’s responsibility. Fridays at 8 p.m., beginning this week.

“America’s Funniest Home Videos”: When this series returns at midseason, former MTV veejay Daisy Fuentes will fill Bob Saget’s shoes as host.

CBS

“Cosby”: The Cos will have his hands full when the house next door is rented to a preschool of 4- and 5-year-olds who love to bother him. Mondays at 8 p.m. Already premiered.

“JAG”: The action-drama gets a new ensign, played by Karri Turner. Tuesdays at 8 p.m., starting this week.

“Dr. Quinn, Medicine Woman”: John Schneider of “Dukes of Hazzard” fame joins the cast as Sully’s best friend. Alex Meneses appears in the recurring role of a strong-willed Mexican-born school teacher. Saturdays at 8 p.m., beginning this week.

“Nash Bridges”: The Don Johnson cop series adds Kelly Hu in a recurring role as a tough Asian American cop. Fridays at 10 p.m. Already premiered.

“Touched by an Angel”: CBS’ most popular entertainment series adds Chris Burke (“Life Goes On”) in the recurring role of a special angel and Alexis Cruz (“Streets of Laredo”) as a streetwise cherub. Sundays at 8 p.m., starting tonight.

FOX

“Beverly Hills, 90210”: Victor Young joins the cast as a free spirit and Hilary Swank plays a single mother with a 6-year-old son. Kathleen Robertson has left the cast. Wednesdays at 8 p.m. Already premiered.

“Melrose Place”: Grant Show, Courtney Thorne-Smith, Laura Leighton and Doug Savant have split the apartment building--and the show. Moving in are Linden Ashby (“Spy Game”) as Dr. Cooper and Jamie Luner (“Savannah”) as his sexy ex-wife out to ruin his life. Mondays at 8 p.m. Already premiered.

NBC

“Caroline in the City”: Sofia Milos becomes a recurring regular as Richard’s (Malcolm Gets) sultry Italian girlfriend. Mondays at 9 p.m., beginning this week.

“ER”: Maria Bello checks in as a pediatrician and British actress Alex Kingston (“Moll Flanders”) makes her U.S. series debut as a surgical resident. Thursdays at 10 p.m., starting this week.

“Fired Up”: Frequent guest star Francesca P. Roberts becomes a regular as the cynical employment office worker who locks horns with Sharon Lawrence. Mondays at 8:30 p.m., beginning this week.

“Homicide: Life on the Street”: Melissa Leo and Max Perlich have left the series. Joining the cast are Jon Seda as a rough-around-the-edges detective; Peter Gerety as a veteran cop; and Callie Thorne as a seasoned homicide detective. Fridays at 10 p.m. Oct. 17.

“Mad About You”: Cynthia Harris and Louis Zorich, who play Paul’s mother and father, become regulars. Anne Ramsay has left the series for CBS’ “Dellaventura.” Tuesdays at 8 p.m., beginning this week.

“Men Behaving Badly”: This struggling sitcom gets a major overhaul in its second season. Justine Bateman and Ron Eldard are history. Ken Marino (“The State”) joins the cast as Jamie’s (Rob Schneider) new roommate and Jenica Bergere plays their new neighbor. Dina Spybey becomes a regular as the object of Jamie’s affections. Sundays at 8 p.m. Sept. 28.

“The Naked Truth”: Tea Leoni’s comedy also gets a face-lift in its second season on NBC. The majority of the supporting cast is gone, including George Wendt. New this season are Chris Elliott as a tabloid photographer, Tom Verica as an investigative reporter, Amy Hill as a photographer and Jim Rash as the head of the tabloid’s research department. Mondays at 9:30 p.m., starting this week.

UPN

“Clueless”: The ABC comedy moves to UPN for its second season. Doug Sheehan (“General Hospital”) joins the cast as Cher’s (Rachel Blanchard) high-powered attorney dad. Tuesdays at 8 p.m., starting this week.

WB

“Nick Freno: Licensed Teacher”: Nick (Mitch Mullany) graduates from elementary school to teaching high school. Jane Sibbett plays the school’s new principal, and Estelle Harris is the voice of the school’s secretary. Sundays at 7 p.m. Already premiered.