Complex sentence: They are attacked by two school bullies (Alex Greenwald and Seth Rogen) who are attempting to rob Roberta's house, and the fight spills into the street where an oncoming car swerves to avoid Roberta but runs over Gretchen, killing her.
Split into simpler sentences: They are attacked by two school bullies (Alex Greenwald and Seth Rogen) who are attempting to rob Roberta's house, and the fight spills into the street. An oncoming car swerves to avoid Roberta but runs over Gretchen, killing her.