Pronoun reference errors give a lot of beginning writers trouble. A pronoun reference error occurs when you use a pronoun like he or she, and it’s not clear what that pronoun refers to. Here is an example:
Who does he refer to? It isn’t clear. A pronoun should clearly refer to its antecedent (the word it replaces), so if the antecedent is not clear, you need to revise. Here’s an example of how you might correct the pronoun reference error:
What about this slight variation?
This sentence isn’t grammatically incorrect, but it is a bit clunky. Because we’ve tweaked the opening half of the sentence so that Darth Vader is the subject (instead of Darth and Luke, like in the previous example), we can replace our second use of Darth Vader with a pronoun to tighten up the writing.