Basic subject-verb agreement is straightforward, but several constructions complicate the match. Compound subjects joined by "and" usually take a plural verb, while subjects joined by "or" or "nor" agree with the nearer subject. Intervening prepositional phrases (The box of chocolates is here) do not change the subject's number. In inverted sentences (There are many reasons), the true subject follows the verb and controls agreement. Mastering these patterns requires looking past surface word order to find the actual subject.
Strip sentences down to their core subject and verb by mentally crossing out prepositional phrases and other intervening material. Practice with sentences where the subject and verb are separated by several words, checking agreement after each reduction.
You already know the basic rule: subjects and verbs must agree in number. The challenge in complex constructions is not the rule itself — it is finding the actual subject when syntax places other nouns between the subject and the verb. The strategy is always the same: strip the sentence down to its grammatical skeleton by mentally removing everything that is not the subject, and then apply the basic rule you already know.
Intervening prepositional phrases are the most common obstacle. "The list of all required items" looks plural because *items* is the nearest noun before the verb — but *list* is the subject. The phrase "of all required items" modifies *list*; it has no bearing on agreement. Bracket it out: [The list] [of all required items] is complete. Once you see the skeleton, the agreement is obvious. This is why prepositional phrases (your prerequisite topic) matter so much: recognizing them as modifiers rather than subjects is the key diagnostic move.
Compound subjects introduce a genuine choice. Subjects joined by *and* are typically plural because they name two separate entities doing something together: "The mayor and the council have decided." But *or* and *nor* follow a different logic — they present alternatives, not combinations. Agreement goes with the subject closest to the verb: "Neither the players nor the coach was prepared" (verb agrees with *coach*); "Neither the coach nor the players were prepared" (verb agrees with *players*). This is called the proximity rule, and it applies whenever *or* or *nor* connects subjects of different numbers.
Inverted sentences require finding the true subject after the verb. In "There are many reasons to consider," the word *there* is a dummy subject — it occupies the subject position but has no grammatical content. The real subject is *reasons*, which follows the verb and controls agreement: "There are many reasons" (not "there is"). Existential *there*-constructions are common and almost always involve this inversion. The test: ask "there are *what*?" The answer is the true subject.
Collective nouns (team, committee, jury, faculty, family) are grammatically singular in American English — they name a single unit, so the verb is usually singular. "The committee has reached its decision." But when the sentence emphasizes individual members acting separately, plural agreement is acceptable: "The jury were unable to agree." The practical guidance: default to singular for American English collective nouns, and only use plural when the sentence explicitly focuses on the members as individuals. The goal in all these cases is the same — match the verb to the real subject, not to the nearest or the most prominent noun.