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Is “A or B” Singular or Plural?

English grammar is anything but straightforward. There are rules you can follow, sure, but every rule comes with an exception, and every exception affects the way you interpret the rule. For instance, is “A or B” singular or plural?

When “A or B” are both singular nouns connected by “or,” you’ll need a singular verb. In contrast, when the subject of your sentence contains two nouns connected by “and,” you’ll need a plural verb. Determining whether “A or B” is singular or plural depends on the joining conjunction and the plurality of the noun closest to the verb for subject-verb agreement. 

For example, if the subject of your sentence contains one singular noun and one plural noun, the noun closest to the verb should agree. Read on to learn more. 

Understanding Subject-Verb Agreement

Subject-verb agreement sounds easy enough, but it can be confusing. A few basic rules illustrate how to ensure that your subjects and verbs “agree” with one another in number, but a few of them can sound contradictory. 

To start, you’ll want to remember that your subject and your verb must agree for your sentence to be grammatically correct. In other words, if your noun is singular, your verb must also be singular. Similarly, if your noun is plural, your verb must also be plural.  

This gets tricky because the way you form a plural in the present tense is different for nouns and verbs, and it’s actually the opposite of what you might expect.

To create a plural noun, you may already know that the general rule is to add an “s” at the end of the word: “dog” becomes “dogs” or “apple” becomes “apples.” However, to create a plural verb, you need to remove the -s from the singular form (source). 

So, for example, the third-person singular form for the verb run would be “runs.”

Before we get into compound subjects, such as with “A and B” or “A or B,” let’s first take a look at a few examples with singular subjects since those are more straightforward and a bit easier to understand.

Subject-Verb Agreement for Singular Subjects: Examples

Take a look at the sentence below. You’ll note that the subject (noun) is in purple and the action verb is in red. 

1.     My dog eats too many treats.

Above, the noun “dog” is singular and in the third person. For the verb to “agree” with the noun (dog) in number, remember that you need to add an “s” to the verb, “eat.” 

Therefore, the verb “eats” is singular — remember, this differs from a noun, where adding an “s” would make it plural. The reason this is confusing for many is the rules are opposite for nouns versus verbs. For the former, you will add an “s,” but for the latter, you’ll take it away.  

Here’s another example, but with the reverse — a plural noun and a singular verb:

2.     The flowers grow quickly in the springtime.

You’ll note that the noun “flowers” is plural. Therefore, for the verb to match, it must also be plural. To create a plural verb form here, we remove the “s.” If you were to write the same sentence with a singular noun (flower), it would look like this:

3.     The flower grows quickly in the springtime.  

Here is the rule you’ll want to remember before we jump into compound subjects:

When writing in the present tense, you ADD an “s” to the singular form to create a plural noun. But, you will REMOVE the “s” from the singular form of a verb to create a plural verb. 
two women smiling in front of computer monitor
Image by Mimi Thian via Unsplash

Subject-Verb Agreement: “A and B” versus “A or B” 

Now that you know the basic rule, we can work through what to do when you have a compound subject. You can create a compound subject when you combine two (or more) nouns with a conjunction, and the nouns then act as a single subject (source).

For the purpose of this article, we’ll focus on “and” versus “or” when speaking of conjunctions that you can use to combine your nouns in creating a compound subject. 

There are other conjunctions, however, including “but,” “because,” “for,” “if,” “when,” etc. Here, though, you’ll really only use “and” or “or” to combine nouns in the subject of your sentence. 

The important idea to remember is that, despite having two nouns as part of your subject, they act as a single subject, meaning one idea. The fact that there is more than one noun does not necessarily mean that your subject is plural. We’ll break this down further next.  

Similar to singular subjects, compound subjects can also be either plural or singular. With that in mind, the rule still applies — your verb must also agree with your compound subject. 

Compound Subjects Joined by “And” 

Compound subjects that you join with the conjunction “and” are always plural.

  • A and B are correct.

Thankfully, that’s a pretty easy rule to remember. So, if you have “A and B” as the subject of your sentence, you will always need to use a plural verb in order to ensure subject-verb agreement.  

Let’s take a look at an example:

1.     My computer and my phone ring at the same time when I get a call. 

This area of grammar is one in which you actually don’t want to think too hard — if you do, you’ll end up confusing yourself. Just remember the rule: Plural verbs REMOVE the “s” from the present tense singular form.   

Above, the compound subject is “My computer and my phone.” Since the conjunction “and” combines “computer” and “phone,” the compound subject is plural. 

Therefore, the verb must also be plural — we know that “ring” is plural here because we’ve removed the “s” from the present tense verb, “rings.” 

Here’s another example:

2.     My dog and my cat sleep next to one another. 

Again, here, we are combining the nouns in the subject with “and,” which means that the compound subject is plural — therefore, the correct way to ensure subject-verb agreement is to use the plural form of the present tense verb, sleep. 

It doesn’t matter what nouns you use to represent “A” and “B.” The important factor is the conjunction. Remember that if you use “and” to create your compound subject, it is a plural compound subject. 

But what if you choose to use “or” instead to show that, rather than both, it is one or the other? 

Compound Subjects Joined by “Or”  

When it comes to combining compound subjects with “or,” things get a little bit trickier. 

The answer depends on the noun nearest the verb. If the noun nearest the verb is plural, your verb will also need to be plural. Conversely, if the noun nearest the verb is singular, your verb should also be singular.

  • Either A or B is correct.
  • Either the A’s or B’s are correct.

The same holds true for the conjunction “nor.” Nor simply means “not,” and you’ll usually precede the subject with “neither.” We’ll take a look at one example like this shortly. But first, let’s take a look at a compound subject combined with “or.”

1.     A piece of cake or two cookies sound lovely, but I’d like only one.   

In this example, “a piece of cake” is singular, while “two cookies” is plural. What we need to do is make sure that the noun nearest the verb agrees. In this case, “cookies” is nearest to the verb. Since “cookies” is plural, we also want to make sure that our verb is plural; thus, “sound” is correct, not “sounds.” 

If we write the same sentence but switch the subjects (nouns) around, it would look like this:

2.     Two cookies or a piece of cake sounds lovely, but I’d like only one. 

Now that the noun nearest the verb is singular, we also need to change the verb so that it is also singular. Thus, we add an “s” and write “sounds,” not “sound.”  

Again, remember that initial rule about creating plural verb forms in the present tense — you’ll always remove the “s” to do so. And, you’ll add it to create the singular form. 

What About Linking Verbs? — Is versus Are

Often, when you are writing a sentence with a compound subject rather than an action verb following the subject, you’ll need to use a linking verb first. Linking verbs, unlike traditional verbs, do not show action. They “link” or connect the subject of your sentence to more information about that subject (source).

A simple sentence with a single subject followed by an action verb may look like this: 


A compound subject with a linking verb will look like this:


There are quite a few linking verbs, but the two we will look at here are “is” and “are.” We need to determine whether we write “Is A and B….” or “Are A and B…”  To answer that question, we need to know whether the subject is plural or singular. 

“A and B Is “ versus “A and B Are”

Identifying whether you should use “is” or “are” after your compound subject isn’t much different than what we have already covered above. Remember that if your compound subject is connected by the conjunction “and,” then your subject is plural.  

The linking verb “is” is singular. Conversely, the linking verb “are” is plural. If your compound subject is plural, you’ll need to use “are” as your linking verb. Like this:

  1. The video game and the controller are working.  

Here is another example:

  1. Cats and dogs are both wonderful pets. 

If, on the other hand, your compound subject is joined by “or,” it is singular, as we’ve discussed above. So, you’ll need to use the linking verb “is” in your sentence. 

  1. Coffee or tea is offered at every breakfast meal provided to guests.  

The same holds true for “nor.” 

  1. Neither coffee nor tea is good, in my opinion. 

Singular and Plural Nouns Joined by “Or”

When it comes to compound subjects consisting of one singular noun and one plural noun, you’ll need to choose the linking verb that agrees with the noun nearest it. Take a quick look at the sentence below: 

One large crate or four small crates are plenty to deliver the groceries.   

Because “crates” is plural and nearest the verb, the correct linking verb is “are.” 

Note that in the above sentence, an adjective is part of the subject — that is okay. It doesn’t change the rule. You’ll simply need to identify whether the verb is singular or plural, regardless of descriptive words that you may choose to include. 

If we switch the above nouns around, your sentence will look like this:

Four small crates or one large crate is plenty to deliver the groceries.  

You’ll notice that, now, the noun nearest the linking verb is singular (one large crate). Therefore, to follow the rule correctly, you’ll need to use the singular linking verb “is” in your sentence.  

Exceptions: When a Single Subject Includes “And” 

As you probably have learned, with every grammatical rule comes at least one exception. And, when it comes to compound subjects, the rules are fairly straightforward — until, that is, you find a compound subject that is actually singular. 

Don’t worry too much about these — you will master them in time and become more familiar with the English language. Here is an example:

1.     Macaroni and cheese is my daughter’s favorite meal.

You may be wondering why “is” is the correct linking verb above, especially since there seems to be a compound subject joined by “and.” If the rule states that compound subjects joined by “and” are plural, why use a singular linking verb?

The reason for this is that despite “and” joining “macaroni” and “cheese,” most understand this to be a singular concept or idea — it is widely recognized as so. 

Therefore, you will write it and use it as a singular subject. Another actually singular yet seemingly compound subject is the idea of “peace and quiet” or “spaghetti and meatballs.” 

Again, there are not too many of these phrases, and you’ll begin to recognize them in time, especially as you become more familiar with English grammar and common concepts and ideas in the language.

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If you’d like to understand more about how to correctly identify and use singular and plural forms in your writing, take a look at Week’s or Weeks’: Singular, Plural, and Possessive.

Final Thoughts

When it comes to understanding singular versus plural with compound subjects, the most important thing to remember is that your subject and verb must agree. If your subject is singular, your verb must also be singular. Conversely, if your subject is plural, your verb must be plural.

This holds true whether you have compound subjects like “A and B” or “A or B” or singular subjects. If you can remember the basic rule above — do not add an “s” to the verb to create a plural verb and add an “s” to create a singular verb — soon enough, you’ll start using the correct verb form without even thinking about it.