Remember that a verbal is a form of a verb that functions as something else in a sentence.
An infinitive is a verbal that can function as noun, adjective, or adverb. It is formed by using "to" + the verb.
The infinitive can appear by itself, or it can be part of a larger infinitive phrase.
Examples of infinitives:
Examples of infinitives or infinitive phrases used as nouns:
1) I like to run. (functions as a direct object)
2) I wanted to cook dinner for my parents. (functions as a direct object)
3) To fly an airplane is a dream of mine. (functions as a subject)
4) I cannot believe you knew to put out grits to attract ants! (functions as a direct object)
Examples of infinitives or infinitive phrases used as adjectives:
1) The fair is the place to go. (tells us which place)
2) I have some jeans to wash. (tells us which jeans)
3) The singer to watch is Joyce. (tells us which singer)
4) The kind of flowers to plant are perennials. (tells us which flowers)
Examples of infinitives or infinitive phrases used as adverbs:
1) To complete the math problem, you divide by x. (tells why to divide)
2) I bought paint to finish the picture for my mom. (tells why I bought paint)
3) To make the cookies, you must add the flour first. (tells why we add flour)