Final answer:
The sentence 'Yo comé una naranja ayer' is incorrect because the verb 'comer' should be conjugated to 'comí' for the first person singular form in the past tense.
Step-by-step explanation:
The sentence 'Yo comé una naranja ayer' is incorrect. The correct form should be 'Yo comí una naranja ayer.' The verb 'comer' is conjugated to 'comí' for the first person singular form in the past tense. The incorrect form 'comé' is a spelling mistake. Remember that in Spanish, verbs change their endings to match the subject.
Learn more about Spanish Verb Conjugation