Straightforward Subject-Verb Agreement

"The dogs barks" sounds wrong the instant you hear it because a plural noun, dogs, is sitting next to a verb built for a singular one. "The dog barks" feels fine because the singular noun and the singular verb form match. That clash or match is the whole test: singular subjects take singular verbs, plural subjects take plural verbs, and your ear usually catches it when the subject sits right next to its verb.

The trouble starts when other words wedge themselves between the subject and the verb. To find the true subject, ignore every word for a second and ask: who or what is doing this action? In 'The committee member files the minutes,' the action belongs to member, a singular noun, so the verb needs the singular form, files, even though minutes sits closer to the verb. In 'Three copies of the report were on the desk,' copies is doing the sitting, not report, so the plural were is correct even though report is the noun right before the verb.

This matters most once sentences get longer, because test writers love to bury the real subject behind a prepositional phrase or a relative clause. A phrase like 'of the report' or a clause like 'who wrote the reports' can drop extra nouns right before the verb, but none of those nouns are the subject. This idea sits underneath every other agreement rule you'll meet: once you can isolate the true subject, matching pronouns, verb tenses, and word choice to it becomes mechanical.