Straightforward Pronoun-Antecedent Agreement

A pronoun is a stand-in. It only works if it copies the one noun it replaces, called the antecedent. If the antecedent is singular, the pronoun must be singular; if plural, the pronoun must be plural. In speech 'a student should bring their book' sounds fine because 'their' has gone neutral and genderless in casual use. On the page, graders still hold the older rule: 'student' is singular, so the pronoun must be singular too, which gives 'his or her.'

To check a pronoun, draw an arrow back to the exact noun it stands for, ignoring everything in between. In 'A student in the 30-person seminar should bring their own copy,' the arrow points to 'student,' not to 'seminar' or '30-person,' so the fix is singular: 'his or her.' Words like everybody, everyone, each, and anybody are always singular, no matter how many people they describe. 'Everybody on the five committees submitted their forms' needs 'a form,' because 'everybody' counts as one grammatical unit even while it refers to a crowd.

Collective nouns such as team, committee, or jury name a group but act as one unit, so they take a singular pronoun by default: 'The team announced its decision.' This sits right next to subject-verb agreement, since the same logic that picks 'its' also picks a singular verb for the same noun. Once you can trace a pronoun to its antecedent and name that antecedent's number, agreement questions become a quick check rather than a guessing game.