Complex sentence: She asks Millhouse if she can eat his cupcake, having just seen A Streetcar named Desire for a class assignment, he takes on the personality of Marlon Brando he decides to be rude and dismissive towards her, refusing her request to eat his cupcake.
Split into simpler sentences: She asks Millhouse if she can eat his cupcake, having just seen A Streetcar named Desire for a class assignment, he takes on the personality of Marlon Brando. Thus, he decides to be rude and dismissive towards her, refusing her request to eat his cupcake.