Answer:
An infinitive is the most basic form of a verb. It is “unmarked” (which means that it is not conjugated for tense or person), and it is preceded by the particle to. Infinitives are known as non-finite verbs, meaning they do not express actions being performed by the subjects of clauses. Instead, infinitives function as nouns, adjectives, or adverbs to describe actions as ideas. Infinitives are distinct from a similar construction known as bare infinitives or the base forms of verbs, which are simply infinitives without the particle to. Although nearly identical, we use them in different ways than “full” infinitives, which we’ll look at later in this section.