Here are some key rules to keep in mind for subject-verb agreement:
1- Singular subjects take singular verbs: When the subject of a sentence is singular, the verb that follows it should also be in the singular form. For example: “She writes a letter.”
2- Plural subjects take plural verbs: When the subject of a sentence is plural, the verb that follows it should also be in the plural form. For example: “They write letters.”
3- Singular indefinite pronouns take singular verbs: Indefinite pronouns like “anyone,” “someone,” “everyone,” and “nobody” are singular and should be followed by singular verbs. For example: “Nobody knows the answer.”
4- Some words appear plural but are treated as singular: Words like “mathematics,” “news,” and “economics” may seem plural, but they are treated as singular nouns and should be paired with singular verbs. For example: “Mathematics is my favorite subject.”
5- Collective nouns can take singular or plural verbs: Collective nouns, which refer to a group of individuals, can take either a singular or a plural verb depending on the context. If the group is seen as a single entity, a singular verb is used. If the individuals within the group are emphasized, a plural verb is used. For example: “The team is winning” (singular), “The team are arguing” (plural).
6- When compound subjects are connected by “and,” use a plural verb: When two or more subjects are connected by “and,” the verb that follows should be in the plural form. For example: “Tom and Jerry are best friends.”
7- When compound subjects are connected by “or,” “either…or,” or “neither…nor,” match the verb to the closest subject: If the subjects connected by these conjunctions are singular, use a singular verb. If the subjects are plural, use a plural verb. For example: “Either John or his brothers are responsible.”