Pronoun case

Every personal pronoun in English changes shape depending on the job it does. Use the subjective case when the pronoun performs the action or follows a linking verb: She wrote the report. Use the objective case when the pronoun receives the action or follows a preposition: The committee thanked her; the letter was addressed to him. Use the possessive case to show ownership: Their proposal won.

Most errors cluster around a few predictable spots. Compound subjects and objects trip writers up because the extra name masks the pronoun's role — "Marcus and me reviewed the data" is wrong, and dropping the other name makes it obvious, since nobody would write "me reviewed the data." The same test fixes the overcorrection in the opposite direction: "between you and I" should be "between you and me," because a preposition takes the objective case.

Comparisons using than or as hinge on the implied words that follow. "She runs faster than he" is correct because the sentence means "faster than he runs." Who and whom follow the same rule as any other pronoun: who is subjective and whom is objective, so you ask whether the clause needs a subject (who called?) or an object (to whom did you speak?). A quick substitution helps — if he fits, use who; if him fits, use whom.

One further caution: possessive pronouns never take an apostrophe. Its, yours, hers, theirs, and whose are already possessive, so an apostrophe in those words signals a contraction instead — it's means "it is."

The Praxis Core Writing exam tests pronoun case in its usage and sentence correction questions, often by burying the pronoun in a compound phrase or a comparison, where the correct form is easy to miss on a first read.