Final answer:
The correct form of decir to complete the sentence 'Los amigos que es divertido' is dicen.
Step-by-step explanation:
The correct form of decir to complete the sentence 'Los amigos que es divertido' is dicen. 'Dicen' is the third person plural form of the verb 'decir' which means 'to say' or 'to tell' in Spanish.
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