Constructing a grammatical sentence can be a tricky business, especially when it comes to conjugating verbs; this refers to the way in which a verb is modified depending on the rest of the sentence.
In this blog post, we focus on subject-verb agreement. Put simply, this is the need to ensure that the subject (i.e. the active entity) and verb (i.e. the action) agree with one another in terms of number. As such, plural subjects must be accompanied by a plural verb and singular subjects require a singular verb.
Plural vs. Singular
The general rule here is to add an ‘-s’ to the verb when using a plural noun for the subject. With the verb ‘run’, for example, the singular form is ‘runs’ while the plural is ‘run’:
Singular = The dog runs through the garden.
Plural = The dogs run through the garden.
Other examples of verbs that follow this convention include:
| Singular | Plural |
| He argues… | They argue… |
| She dances… | They dance… |
| It drinks… | They drink… |
This isn’t always the case, especially when first-person pronouns are used (e.g. we’d say ‘I argue…’, not ‘I argues’, even though ‘I’ is singular).
There are also some irregular verbs in English that do not follow the typical rules for conjugation. In terms of subject-verb agreement, the most common is ‘be’. We can see the various forms this verb takes when we consider how it’s used in relation to singular and plural pronouns:
| Singular | Plural | |
| First Person | I am… | We are… |
| Second Person | You are… | You are… |
| Third Person | He/She/It is… | They are… |
As the table above shows, the verb ‘be’ is modified to either ‘am’, ‘are’ or ‘is’ in the singular depending on the grammatical person used. However, it becomes ‘are’ in the plural.
Confused? That’s okay. Needless to say, the key here is mostly practice, so try to familiarise yourself with the correct modifications for any irregular verbs that you use regularly.
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Compound Subjects
Another tricky factor in subject-verb agreement is how to modify the verb in a sentence containing a compound subject. The subject of the sentence is said to be ‘compound’ when it contains two or more nouns linked by the words ‘and’, ‘or’ or ‘nor’.
When two singular nouns in the subject of a sentence are connected with ‘and’, the verb used should be plural:
The dog and the cat are digging up the garden.
When two singular words are connected by ‘or’ or ‘nor’, however, a singular verb should be used:
Either the dog or the cat is digging up the garden.
Neither the dog nor the cat is digging up the garden.
When a compound subject contains both a singular and a plural noun connected by ‘or’ or ‘nor’, moreover, the rule is to modify the verb based on the part of the subject that is nearest the verb in the sentence:
Either the dog or the cats are digging up the garden.
Neither the cats nor the dog is digging up the garden.