Final answer:
The appropriate infinitive expression to complete the sentence is 'a ir de viaje.'
Step-by-step explanation:
Maria quiere ir de viaje. The appropriate infinitive expression to complete the sentence is 'a ir de viaje.' In this case, the verb 'ir' is used in its infinitive form, preceded by the preposition 'a' to indicate the action of going on a trip. The sentence can be translated as 'Maria wants to go on a trip.'
Learn more about Infinitive expressions