Complex sentence: Doc even had at one point implied that Marty could possibly have a similar fate, leading Marty to become more apprehensive of his actions.Biff Tannen's great-grandfather, Buford, goaded Marty into a showdown, which ended with Marty victorious over Buford.
Split into simpler sentences: Doc even had at one point implied that Marty could possibly have a similar fate, leading Marty to become more apprehensive of his actions. After Biff Tannen's great-grandfather, Buford, goaded Marty into a showdown, which ended with Marty victorious over Buford.