Subject-verb agreement means the verb must match the subject in number (singular or plural).
Core rule: singular subjects take singular verbs; plural subjects take plural verbs.
- "The dog runs fast." — singular
- "The dogs run fast." — plural
Third-person -s: In the present tense, add -s to the verb for third-person singular (he, she, it).
- "He plays guitar." — third-person singular
- "They play guitar." — third-person plural
Compound subjects with "and" are plural:
- "Tom and Jerry are friends."
Subjects with "or / nor" — the verb agrees with the closest subject:
- "Neither the teacher nor the students were ready."
Indefinite pronouns (everyone, somebody, nobody, each) are singular:
- "Everybody wants to be happy."
Collective nouns (team, family, audience) can be singular or plural depending on whether the group acts as one unit or as individuals:
- "The team is winning." — single unit
- "The team are arguing among themselves." — individuals