The antecedent of the pronoun is the word the pronoun refers to. The antecedent usually appears before the pronoun—earlier in the sentence or in a previous sentence. Pronouns and antecedents are said to agree when they match up in person, number, and gender.

Using compound antecedents

Compound antecedents joined by and require plural pronouns.

A compound antecedent preceded by each or every, however, takes a singular pronoun.

Every plant and animal has its own ecological niche.

With a compound antecedent joined by or or nor, the pronoun agrees with the nearest antecedent. If the parts of the antecedent are of different genders or persons, however, this kind of sentence can be awkward.

When a compound antecedent contains both singular and plural parts, the sentence may sound awkward unless the plural part comes last.

Using collective-noun antecedents

A collective-noun antecedent (herd, team, audience) that refers to a single unit requires a singular pronoun.

When such an antecedent refers to the multiple parts of the unit, however, it requires a plural pronoun.

Using indefinite-pronoun antecedents

Indefinite pronouns do not refer to specific persons or things. A pronoun whose antecedent is an indefinite pronoun should agree with it in number. Many indefinite pronouns are always singular (as with one); a few are always plural (as with many). Some can be singular or plural depending on the context.

One of the ballerinas lost her balance.

Many in the audience jumped to their feet.

Some of the antique furniture was showing its age. [singular meaning for some]

Some of the local farmers abandoned their land. [plural meaning for some]