1. Lesson Overview
In this lesson, you will learn the fundamental rule of subject–verb agreement, which requires the verb form to match the subject in number and sometimes in person.
In English grammar, agreement mainly affects the present simple tense, where singular and plural subjects take different verb forms.
Example:
The researcher analyses the data.
(Singular subject → singular verb)
The researchers analyse the data.
(Plural subject → plural verb)
Although this rule seems simple, learners often make mistakes when sentences contain additional modifiers or complex structures.
By the end of this lesson, you will be able to:
-
understand the basic rule of subject–verb agreement
-
recognise how singular and plural subjects affect verb forms
-
identify how verbs change in the present simple tense
-
avoid common beginner errors in subject–verb agreement
2. Concept Introduction
Consider the following examples:
The experiment succeeds.
The experiments succeed.
| Subject | Number | Verb Form |
|---|---|---|
| experiment | singular | succeeds |
| experiments | plural | succeed |
The verb must match the number of the subject.
This rule applies to most verbs in the present simple tense.
3. Core Explanation
Subject–verb agreement means that the verb must correspond to the subject in number.
The basic principle is:
Singular subject → singular verb
Plural subject → plural verb
Example:
| Sentence | Agreement |
|---|---|
| The researcher writes the report. | Correct |
| The researchers write the report. | Correct |
In the present simple tense, singular verbs usually add -s or -es.
Example:
The scientist studies the results.
Plural subjects do not add -s to the verb.
Example:
The scientists study the results.
4. Rule Table
Basic Subject–Verb Agreement
| Subject | Verb Form | Example |
|---|---|---|
| Singular subject | singular verb | The experiment succeeds. |
| Plural subject | plural verb | The experiments succeed. |
Present Simple Verb Forms
| Subject | Verb | Example |
|---|---|---|
| I / You / We / They | base verb | They analyse the data. |
| He / She / It | verb + s | She analyses the data. |
Verb Forms with “Be”
| Subject | Verb | Example |
|---|---|---|
| I | am | I am analysing the results. |
| He / She / It | is | The device is functioning. |
| You / We / They | are | The samples are ready. |
5. Usage
1. Agreement with singular subjects
Example:
The researcher writes the report.
2. Agreement with plural subjects
Example:
The researchers write the report.
3. Agreement with third-person singular subjects
Example:
The scientist analyses the samples carefully.
4. Agreement with “be” verbs
Example:
The experiment is successful.
5. Agreement with plural nouns
Example:
The results are accurate.
6. Signal Words
Certain sentence elements help identify whether the subject is singular or plural.
| Indicator | Example |
|---|---|
| singular noun | The researcher analyses the results. |
| plural noun | The researchers analyse the results. |
| third-person singular pronoun | She writes the report. |
| plural pronoun | They write the report. |
| singular pronoun | It produces reliable results. |
Recognising the true subject helps determine the correct verb form.
7. Special Cases
Subjects Separated from Verbs
Sometimes phrases appear between the subject and the verb.
Example:
The results of the experiment are accurate.
The subject is results, not experiment.
Singular Nouns Ending in “s”
Some singular nouns appear plural but take singular verbs.
Example:
Physics is a complex subject.
8. Additional Notes
Subject–verb agreement errors often occur when writers focus on a nearby noun rather than the true subject.
Example:
Incorrect:
The results of the experiment is reliable.
Correct:
The results of the experiment are reliable.
Always identify the true subject before selecting the verb.
9. Common Errors
⚠ Singular subject with plural verb
Incorrect:
The experiment succeed.
Correct:
The experiment succeeds.
Explanation:
Singular subjects require singular verbs.
⚠ Plural subject with singular verb
Incorrect:
The researchers analyses the data.
Correct:
The researchers analyse the data.
Explanation:
Plural subjects use base verb forms.
⚠ Missing -s in third-person singular
Incorrect:
She analyse the samples.
Correct:
She analyses the samples.
Explanation:
Third-person singular verbs usually add -s or -es.
⚠ Incorrect agreement with “be”
Incorrect:
The results is reliable.
Correct:
The results are reliable.
Explanation:
Plural subjects require are, not is.
⚠ Confusing nearby noun with subject
Incorrect:
The results of the experiment is accurate.
Correct:
The results of the experiment are accurate.
Explanation:
The subject is results, which is plural.
10. Lesson Mastery
After completing this lesson, you should now be able to:
✅ apply the basic rule of subject–verb agreement
✅ recognise how singular and plural subjects determine verb forms
✅ identify verb changes in the present simple tense
✅ avoid common beginner errors in subject–verb agreement