Final answer:
The linking verb in the sentence is 'became' and the predicate noun is 'author'.
Step-by-step explanation:
The linking verb in this sentence is 'became'. The predicate noun in this sentence is 'author'. J. K. Rowling became a best-selling author after publishing Harry Potter and the Sorcerer's Stone. In this sentence, the linking verb 'became' connects the subject 'J. K. Rowling' to the predicate noun 'author', which renames or identifies the subject.
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