Complex sentence: Grogan's dog Marley appeared in the movie "The Last Home Run" when he was on film for less than 2 minutes when a van pulls up to a curb and a girl steps out and a boy steps out with Marley.
Split into simpler sentences: Grogan's dog Marley appeared in the movie "The Last Home Run". He was on film for less than 2 minutes when a van pulls up to a curb and a girl steps out and a boy steps out with Marley.