1. Preposition: This is the most common use of "into." It shows the relationship between a noun or pronoun and another element in the sentence, often indicating movement or direction.
* Example: "The cat jumped into the box."
2. Adverb: Less common, "into" can act as an adverb, modifying a verb or adjective, meaning "with great enthusiasm" or "intensely."
* Example: "She threw herself into the work."
3. Idiomatic expression: "Into" can be part of an idiom, where the meaning is not literal.
* Example: "She's into rock music." (meaning she enjoys it)
To determine the part of speech, consider the context of the sentence and how "into" is being used.