Which part of speech can function as a subject or object within a sentence?

Pronouns are indeed versatile parts of speech that can function as subjects or objects within sentences. When a pronoun acts as a subject, it performs the action of the verb, as seen in sentences like "She runs fast." Here, "she" is the subject. In contrast, when a pronoun serves as an object, it receives the action of the verb, as in "I saw him." In this case, "him" is the object of the verb "saw."

This flexibility allows pronouns to replace nouns in various sentence constructions, which is essential for avoiding repetition and improving sentence flow. They can stand in for people, places, or things, making them a critical element of sentence structure. In everyday language, pronouns like "he," "she," "it," "they," and "them" are commonly used in both subject and object positions, showcasing their dual function effectively.