Subject is the person who performs the action.
Verb is the action itself.
Subject Verb Agreement means there must be the agreement between the subject and the form of the verb i.e both are singular or both are plural.
Subject Verb Agreement Rules –
1. When a sentence has a subject made up of a group of words that are adjoined with the help of conjunction ‘are’, then consider this as plural subject, hence plural verb will be used.
2. Collective Nouns are considered as singular and hence singular verb will be used.
3. Indefinite pronouns always take a singular form of the verb irrespective of the noun.