Final answer:
The sentence 'Es mi tercer año en la universidad' is grammatically correct in Spanish.
Step-by-step explanation:
The sentence 'Es mi tercer año en la universidad' is grammatically correct in Spanish. 'Es' is the third person singular form of the verb 'ser' (to be) which agrees with the subject 'mi tercer año' (my third year). 'en la universidad' means 'in the university'. Therefore, the sentence translates to 'It is my third year in the university'.
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