Adena wants Sam to learn to change a tire.

to learn -infinitive used as adj.
to change - infinitive used as an adverb?

Actually, in this sentence, the phrase "to change a tire" is used as an infinitive phrase functioning as a noun.

Infinitive phrases can serve different grammatical roles in a sentence, and in this case, "to change a tire" is being used to describe the purpose or goal of the action "wants." It explains why Adena wants Sam to learn.

To clarify, here's the breakdown of the sentence:

- "Adena wants" is the main clause of the sentence, with "wants" being the main verb and "Adena" being the subject.
- "Sam to learn" is an object of the verb "wants." Here, the verb "learn" is in its base form, or infinitive form, and it is being used as an adjective to modify the noun "Sam." The entire phrase "Sam to learn" functions as a direct object, indicating what Adena wants.
- "to change a tire" is an infinitive phrase that acts as an adverbial modifier, indicating the purpose or goal of Sam learning. It tells us what Sam is expected to learn.

So, to summarize, both "to learn" and "to change" are used as infinitives, but they serve different grammatical functions in this sentence: "to learn" acts as an adjective modifying "Sam," and "to change a tire" acts as an adverbial modifier describing the purpose of Sam's learning.