Compound subjects shape sentence structure, but agreement becomes tricky when a writer adds phrases like as well as and together with. Many people assume these expressions create a plural subject, yet standard grammar treats them differently from and. In careful English, the verb usually agrees with the main subject, not with the added phrase. That distinction matters in academic writing, business communication, journalism, and exam settings because subject-verb agreement signals control, clarity, and credibility.
In my editing work, this error appears constantly: “The manager, together with her assistants, are reviewing the file.” The sentence sounds plural because assistants sits next to the verb, but the grammatical subject is still manager, so the standard verb is is reviewing. Understanding that principle is essential not only for agreement but also for mastering sentence structure as a whole. This article serves as a hub for sentence structure within grammar, connecting compound subjects to related issues such as modifiers, appositives, prepositional phrases, coordination, punctuation, and stylistic emphasis.
To use these patterns correctly, you need three key terms. A compound subject usually means two or more subjects joined by a coordinator such as and, as in “Maya and Leo are presenting.” Subject-verb agreement means the verb form matches the grammatical number of the subject. A parenthetical addition is an inserted phrase that adds information without changing the core agreement pattern. In standard usage, as well as, along with, together with, in addition to, and similar expressions often function as parenthetical additions rather than true coordinators.
What counts as a compound subject in sentence structure
A true compound subject uses coordination that gives equal grammatical weight to each noun or noun phrase. The clearest signal is and: “The teacher and the principal are meeting.” Because two subjects are joined as a unit, the verb is plural. By contrast, “The teacher, as well as the principal, is meeting parents” does not create the same structure. The principal is added information, not a second head of the subject. This is why reliable style references and usage guides consistently distinguish between coordination and supplementation.
This distinction helps you parse sentences accurately. If you strip out the inserted phrase, the agreement becomes obvious: “The teacher is meeting parents.” Add the supplemental phrase back and nothing changes: “The teacher, as well as the principal, is meeting parents.” I teach writers to test difficult sentences this way because it prevents attraction errors, where the nearest noun wrongly pulls the verb into plural form. Attraction errors are especially common when a plural noun stands between the subject and the verb.
Sentence structure depends on hierarchy, not proximity. English verbs do not agree with the closest noun; they agree with the governing subject. That rule also explains why prepositional phrases do not control agreement: “The list of changes is attached,” not “are attached.” Phrases with together with work similarly. The structure may feel expansive, but grammatically it remains anchored to one core subject unless the sentence is recast with and.
Agreement rules for as well as, together with, and similar phrases
The standard rule is direct: when a singular subject is followed by as well as, together with, along with, or in addition to, use a singular verb. Example: “The editor, along with two interns, approves the schedule.” When the main subject is plural, use a plural verb: “The editors, along with two interns, approve the schedule.” The added phrase does not alter number; it only adds accompanying information.
These expressions often create confusion because they imply inclusion in meaning while remaining singular in syntax. Semantics and grammar do not always align. “The CEO, as well as the board members, supports the merger” means more than one person supports it, but the sentence is built around the singular subject CEO. Writers who want grammatical structure and semantic emphasis to match should revise to “The CEO and the board members support the merger.”
Use punctuation as a signal. Commas often appear around these additions, especially when the phrase interrupts the subject and verb: “Jordan, together with his cousins, is traveling.” The commas reinforce the parenthetical nature of the phrase. However, punctuation alone does not determine agreement. Even without commas in a restrictive context, the verb still agrees with the head subject: “Jordan together with his cousins is traveling across Spain this summer.”
| Structure | Example | Correct Verb | Reason |
|---|---|---|---|
| True compound subject with and | The coach and the captain ___ ready. | are | Two equal subjects form a plural subject. |
| Singular subject + as well as | The coach, as well as the captain, ___ ready. | is | The head subject is singular. |
| Singular subject + together with | The coach, together with the players, ___ ready. | is | The added phrase does not change agreement. |
| Plural subject + along with | The coaches, along with the trainer, ___ ready. | are | The head subject is plural. |
Why writers make agreement mistakes in these constructions
The main cause is interference from nearby nouns. In psycholinguistics, this is often described as attraction: a plural noun close to the verb increases the chance of a plural verb, even when the grammatical subject is singular. Native speakers make this mistake in speech, and hurried writers carry it into formal prose. “The introduction, together with the notes, were revised” is a classic attraction error.
Another cause is overgeneralizing from meaning. If several people or things are involved, writers intuitively reach for a plural verb. But formal agreement follows syntax first. This matters in edited prose, legal drafting, and standardized tests, where readers expect conventional agreement. Microsoft Word and Grammarly can catch some cases, but automated tools are inconsistent when punctuation is unusual or the sentence is long. Human review remains important.
A third cause is confusion between notional agreement and formal agreement. English sometimes allows notional agreement, especially with collective nouns in British usage, as in “The team are winning.” But phrases like as well as still do not usually create a plural subject in standard edited English. If you want plural agreement beyond doubt, choose a genuine compound subject with and or rewrite the sentence for simplicity.
How these patterns connect to the wider sentence structure hub
This topic belongs at the center of sentence structure because it touches nearly every major pattern. First, it teaches writers to identify the head of the subject phrase. That skill carries into articles on simple subjects, complete subjects, and interrupted subjects. Second, it clarifies how modifiers work. Phrases beginning with as well as and together with behave much like interrupting modifiers: they add detail, but they do not become the grammatical engine of the clause.
Third, it links directly to punctuation. Parenthetical commas can reveal structure and improve readability, especially in long noun phrases. Fourth, it connects to coordination and subordination. Students who confuse and with as well as often also struggle with coordinating conjunctions, correlative conjunctions, and cumulative modifiers. Finally, this issue supports stronger revision habits. When a sentence feels unstable, reducing it to the subject and verb usually exposes the problem immediately.
In practical terms, this hub should lead readers to related subtopics such as subject-verb agreement, phrases versus clauses, appositives, interrupting elements, parallel structure, and sentence clarity. Mastering one pattern in isolation helps, but mastering the system matters more. Sentence structure is not a list of separate rules; it is a method of seeing how grammatical parts relate to each other inside a complete thought.
Best practices, exceptions, and editing strategies
The safest practice is simple: if you mean a true joint subject, use and; if you mean an added companion element, use as well as or together with and keep the verb aligned with the head subject. This choice also affects emphasis. “The founder and the designers are attending” highlights equal participation. “The founder, together with the designers, is attending” keeps the focus on the founder.
There are stylistic gray areas. In informal speech, people sometimes use plural verbs after these expressions because the meaning feels collective. You will hear sentences like “The singer, along with her band, are touring.” In conversation, that may pass unnoticed. In formal writing, however, most editors change it to is touring or recast the sentence entirely. Consistency with standard agreement is the stronger choice for publication, academic work, and workplace documents.
During revision, I recommend a four-step check. Identify the head subject. Remove interrupting phrases. Match the verb to that head subject. Then ask whether the sentence would be clearer if recast with and. This method works across many grammar problems, not just this one. It improves precision, reduces ambiguity, and makes long sentences easier for readers to process.
Compound subjects are easy when writers separate meaning from structure. And creates a true plural subject in most cases; as well as and together with usually do not. Once you identify the head subject, agreement becomes straightforward, punctuation makes more sense, and revision gets faster. That is why this issue belongs at the heart of sentence structure: it trains you to see the framework of a sentence rather than just the words nearest the verb.
The practical takeaway is clear. If the added phrase is parenthetical, the verb follows the main subject. If both elements are equal subjects, use and and a plural verb. Apply that distinction in emails, reports, essays, and web copy, and your sentences will read as more precise and professional. For anyone building stronger grammar skills, this is one of the highest-value rules to master because it improves both correctness and style.
Review your recent writing and look for subjects interrupted by extra phrases. Test each sentence by removing the insertion and checking the verb. That single habit will sharpen your control of agreement and strengthen your command of sentence structure across the entire grammar topic.
Frequently Asked Questions
Do phrases like “as well as” and “together with” create a plural subject?
No. In standard English grammar, phrases such as as well as and together with do not usually turn a singular subject into a plural one. They add extra information about who or what is included, but they do not function the same way as and. That is the key agreement rule. If the main subject is singular, the verb is usually singular: The manager, as well as the assistants, is attending the meeting. If the main subject is plural, the verb is usually plural: The managers, together with the assistants, are attending the meeting.
This matters because many writers instinctively focus on the noun nearest the verb rather than the true grammatical subject. That often leads to errors such as The manager, as well as the assistants, are attending, which sounds natural to some ears but does not follow formal agreement conventions. In academic writing, professional communication, journalism, and test settings, readers generally expect the verb to agree with the main subject alone. A useful test is to temporarily remove the inserted phrase. If the sentence still makes sense, the remaining subject will show you the correct verb form: The manager is attending. That confirms is, not are.
How is “as well as” different from “and” in subject-verb agreement?
The difference is grammatical as well as stylistic. The conjunction and usually joins two subjects into one compound plural subject, so it normally takes a plural verb: The editor and the publisher are in agreement. By contrast, as well as introduces an accompanying element rather than forming an equal grammatical partnership. In formal usage, the first noun remains the true subject: The editor, as well as the publisher, is in agreement.
This distinction affects meaning and emphasis. With and, both elements are presented as equally central. With as well as, the first element is primary and the second is additional. That is why the agreement stays with the first subject. The same principle applies to similar expressions such as along with, together with, in addition to, and accompanied by. For example, The teacher and the student were recognized gives equal weight to both people, while The teacher, together with the student, was recognized keeps teacher as the grammatical center. For precise writing, especially in formal contexts, treating these structures differently from and is essential.
What is the easiest way to choose the correct verb when a sentence includes “together with” or “as well as”?
The simplest method is to identify the main subject and ignore the inserted phrase for a moment. Writers often get distracted by the noun closest to the verb, but proximity does not control agreement in this construction. The controlling noun is the head of the subject phrase, usually the noun that appears before as well as or together with. For example, in The principal, together with several teachers, was present, the main subject is principal, so the verb is singular: was.
A reliable editing technique is to remove the interrupting phrase and read the sentence again. The principal was present clearly sounds correct, so that confirms the agreement. The same strategy works in plural cases: The principals, as well as several teachers, were present. Remove the added phrase and you get The principals were present. This approach is especially helpful in long or complex sentences, where extra modifiers can hide the real subject. It is also useful in timed exams and professional editing because it reduces the decision to one question: what is the true subject, singular or plural? Once that is clear, the correct verb choice usually becomes obvious.
Are there situations where writers use plural agreement after “as well as” or “together with”?
In very informal speech and less edited writing, some people use plural verbs because the sentence refers to more than one person or thing in a general sense. For example, someone might say, The coach, as well as the players, are excited. This reflects not the formal grammar of the construction, but the speaker’s sense that multiple people are involved. That pattern does appear in real-world usage, especially in conversation, where meaning often matters more than strict agreement rules.
However, in careful written English, singular or plural agreement should still follow the main subject, not the noun inside the added phrase. If the subject is singular, formal style prefers is, was, or another singular verb form. If the subject is plural, formal style prefers a plural verb. Because your article topic concerns agreement criteria, the safest guidance is this: in academic papers, business documents, news writing, reports, and grammar-focused exams, treat as well as and together with as parenthetical or supplementary expressions, not as markers of a true compound plural subject. That choice aligns with standard grammar expectations and avoids criticism from careful readers.
Why is this rule so important in academic, business, and exam writing?
Subject-verb agreement is a small feature with a large effect on credibility. When a writer handles structures like as well as and together with correctly, the sentence reads as controlled, precise, and grammatically confident. In academic writing, that precision supports clear argumentation and helps readers focus on the content rather than the form. In business communication, it contributes to professionalism and reduces the impression of carelessness. In journalism, it supports consistency and editorial standards. In exams, it can directly affect scores because agreement questions often test whether students can distinguish between a true compound subject and a subject followed by an added phrase.
This rule also improves clarity. Compare The director, as well as the advisors, approves the policy with The director and the advisors approve the policy. The first sentence identifies the director as the principal decision-maker, while the second presents a genuinely shared subject. Choosing the right structure therefore influences both grammar and meaning. Mastering this distinction helps writers do more than avoid mistakes; it helps them express relationships between ideas more accurately. That is why understanding agreement with as well as and together with is not just a technical point of grammar, but a practical tool for strong, polished communication.
