Final answer:
The word 'after' is a preposition.
Step-by-step explanation:
The word 'after' is a preposition in the given sentence: May comes after April. A preposition is a word that shows the relationship between a noun (or pronoun) and another word in the sentence. In this case, 'after' is showing the relationship between the month 'May' and the month 'April'.
Learn more about Parts of speech