Subject-verb agreement is a fundamental aspect of grammar that every writer needs to know. It is an essential tool for clear communication and effective writing. Subject-verb agreement refers to the grammatical match between subjects and verbs in a sentence. A subject and a verb must always agree in number and person. Here are nine rules of subject-verb agreement to help you master this essential element of grammar.

1. Singular subjects take singular verbs: A singular subject should take a singular verb. For example, «The dog barks» (not bark).

2. Plural subjects take plural verbs: A plural subject should take a plural verb. For example, «The dogs bark» (not barks).

3. Compound subjects take plural verbs: A compound subject (two or more subjects joined by «and») should take a plural verb. For example, «John and Lisa are going to the party.»

4. Singular indefinite pronouns take singular verbs: Singular indefinite pronouns (someone, anybody, everyone, nobody, etc.) should take singular verbs. For example, «Everyone is coming to the party.»

5. Plural indefinite pronouns take plural verbs: Plural indefinite pronouns (some, few, many, etc.) should take plural verbs. For example, «Few have read the book.»

6. Collective nouns take singular verbs when referring to the group as a whole: Collective nouns (team, band, class, etc.) should take singular verbs when referring to the group as a whole. For example, «The team is playing well.»

7. Collective nouns take plural verbs when referring to the individuals within the group: Collective nouns should take plural verbs when referring to the individuals within the group. For example, «The team are all wearing their jerseys.»

8. Indefinite expressions like «a lot» or «a number of» take plural verbs: Indefinite expressions like «a lot» or «a number of» should take plural verbs. For example, «A lot of people have read the book.»

9. Nouns that end in «-s» but are singular in meaning take singular verbs: Nouns that end in «-s» but are singular in meaning (politics, news, economics, etc.) should take singular verbs. For example, «Politics is a dirty game.»

In conclusion, subject-verb agreement is a critical aspect of writing, and by following these nine rules, you can ensure that your writing is clear, effective, and grammatically correct. Remember to always pay attention to the number and person of your subjects and verbs to avoid making common grammatical errors.