Here's a breakdown:
* Noun: The infinitive can act as the subject, object, or complement of a sentence.
* Subject: *To learn* is my favorite hobby.
* Object: I love *to read*.
* Complement: My goal is *to graduate*.
* Adjective: The infinitive can modify a noun or pronoun.
* *To see* the Eiffel Tower is on my bucket list. (Modifies "Tower")
* He has a *lot to learn* about computers. (Modifies "lot")
* Adverb: The infinitive can modify a verb, adjective, or another adverb.
* She is strong enough *to lift* the weight. (Modifies "strong enough")
* They were eager *to start* the game. (Modifies "eager")
It's important to note that infinitives can also be used as part of other grammatical structures, such as prepositional phrases or as the complement of a noun phrase.
Example:
* I have no desire *to go* (prepositional phrase)
* She is the first person *to arrive* (complement of a noun phrase)