Subject-Verb Agreement with Complex Subjects — I can use subject–verb agreement accurately with complex subjects (phrases, prepositional interruptions).

Every language has its own rules about how words fit together, and English is no exception. One of the oldest and most important rules in English grammar is subject–verb agreement — the idea that the verb in a sentence must match the subject in number. A singular subject needs a singular verb, and a plural subject needs a plural verb. This rule has deep roots in the history of the English language.

Old English, the language spoken in England over a thousand years ago, had far more verb endings than modern English does. Verbs changed their form depending on the person (first, second, or third) and the number (singular or plural) of the subject. Over centuries, most of those endings disappeared, but one key distinction survived: the difference between singular and plural in the present tense, especially for third-person subjects. That is why we still say "she runs" but "they run." Understanding why this rule stuck around helps us see why it still matters today.

So here is the question this lesson tackles: what happens when the subject of a sentence is not just a simple noun like "dog" or "students"? What if the subject is buried inside a long phrase, or a prepositional phrase sneaks in between the subject and the verb? These complex subjects are where most agreement errors happen — and learning to handle them is the key to polished, clear writing.

Before we dive into tricky sentences, let's nail down the foundational ideas. Subject–verb agreement follows a simple core rule, but the challenge is applying it when sentences get complicated. The principles below will serve as your toolkit for every agreement question you encounter.

The diagram below shows how a sentence can be broken apart to reveal the true subject hidden behind prepositional interruptions. Notice how the prepositional phrase sits between the subject and the verb, creating a potential trap. By visually crossing out the interruption, the correct agreement becomes clear.

As you can see, the word "roses" is plural, and it sits right next to the verb. That closeness is exactly what tricks people into writing "The bouquet of red roses sit on the table." But "roses" is inside a prepositional phrase — it describes the bouquet, not the action. The cross-out strategy makes the correct choice obvious every time.

Let's look at the specific patterns that create complex subjects. Each pattern has its own rule, but they all come back to one big idea: find the true subject and ignore everything else.

Pattern 1: Prepositional Phrase Interruptions

A prepositional phrase starts with a preposition (of, in, with, at, by, for, between, among, etc.) and ends with a noun or pronoun called the object of the preposition. The object of a preposition is never the subject of the sentence. Common prepositions that cause confusion include "of," "along with," "together with," "as well as," "in addition to," and "accompanied by." Even though phrases like "along with her friends" sound like they add to the subject, they are grammatically prepositional and do not change the subject's number.

Pattern 2: Subjects with Appositives or Relative Clauses

An appositive (a renaming phrase set off by commas) and a relative clause (beginning with who, which, or that) can also interrupt the connection between subject and verb. For example: "My neighbor, who owns three dogs, walks every morning." The verb "walks" agrees with "neighbor" (singular), not "dogs."

Pattern 3: Compound Subjects with "And," "Or," "Nor"

When two subjects are joined by "and," they usually form a plural subject: "The dog and the cat are playing." However, when subjects are joined by "or" or "nor," the verb agrees with the subject closer to the verb: "Neither the students nor the teacher was ready." Here, "teacher" is closer and singular, so the verb is singular.

Pattern 4: Inverted Sentence Order

Sometimes the subject comes after the verb, especially in sentences beginning with "there" or "here." In "There are three reasons for this decision," the subject is "reasons" (plural), not "there." Always look past "there" or "here" to find the real subject.

Some subjects are especially sneaky because they look plural but are actually singular, or vice versa. The chart below organizes these tricky cases so you can reference them quickly.

Let's walk through a tricky sentence from start to finish. The sentence is: "The collection of rare stamps belonging to my grandfather _____ (is/are) worth thousands of dollars."

Knowing the rules is one thing, but knowing where people commonly slip up is just as important. The table below shows the most frequent agreement mistakes and the corrections you can make.

Subject–verb agreement with complex subjects is a gateway skill. Once you master it, you are ready to tackle even more advanced grammar concepts. The table below shows how the skills you have learned in this lesson connect to topics you will encounter in higher-level English and writing courses.

As you move into AP English, college-level writing, or professional communication, subject–verb agreement with complex subjects will be second nature. The analytical habit of finding the true subject before choosing a verb trains your brain to parse sentences carefully — a skill that also helps with reading comprehension, editing, and even learning other languages that have more complex agreement systems.

Test your understanding with these five problems. Each one increases in difficulty. For every sentence, choose the correct verb and explain your reasoning.