What is the function of a preposition in a sentence?

The function of a preposition in a sentence is to sit before a noun, forming a prepositional phrase that indicates relationships of time, place, direction, or manner. Prepositions connect nouns or pronouns to other words in a sentence, providing essential context that clarifies where, when, or how something occurs. For example, in the phrase "in the park," the preposition "in" establishes a relationship between the noun "park" and the action or state being described.

The other functions mentioned in the choices do not accurately describe what a preposition does. Linking independent clauses is a function of conjunctions. Modifying a verb falls under the role of adverbs or adjectives, and expressing an action is typically the role of verbs, rather than prepositions. Thus, the correct identification of a preposition's role in relation to nouns is what makes the chosen answer valid.