Final answer:
The appropriate form of the verb 'poder' to fill in the blank is 'pueda'. It means 'to be able to' or 'can' in Spanish.
Step-by-step explanation:
The appropriate form of the verb poder to fill in the blank in the given sentence is pueda. The sentence should be: Dudo que yo pueda ir a la fiesta.
In Spanish, the verb poder means 'to be able to' or 'can'. In this sentence, 'Dudo que yo pueda ir a la fiesta' translates to 'I doubt that I can go to the party'.
The correct form of the verb poder to use here is the present subjunctive form, which is pueda for the first person singular.
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