1. Lesson Overview
In this lesson, you will learn how subject–verb agreement works when the subject contains complex noun phrases.
In many sentences, the subject is followed by additional phrases or modifiers. These elements may make it difficult to identify the true subject, which determines the correct verb form.
Common structures that cause confusion include:
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subjects followed by prepositional phrases
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expressions such as a number of / the number of
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phrases showing quantity or measurement
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subjects followed by relative clauses
Understanding these structures helps learners recognise the core subject and choose the correct verb.
By the end of this lesson, you will be able to:
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identify the true subject in complex noun phrases
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apply agreement rules when subjects include prepositional phrases
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distinguish between a number of and the number of
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apply agreement rules with quantities and measurements
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avoid common learner errors involving complex subject structures
2. Concept Introduction
Consider the following sentence:
The results of the experiment are reliable.
At first glance, the noun experiment appears close to the verb, but the true subject is results.
| Phrase | Function |
|---|---|
| The results | subject |
| of the experiment | modifying phrase |
Because results is plural, the verb must also be plural.
3. Core Explanation
Complex noun phrases often include additional information that modifies the subject. However, these modifiers do not change the number of the subject.
Example:
The results of the experiment are accurate.
The subject is results, not experiment.
Another example:
The quality of the samples is excellent.
Here the subject is quality, which is singular.
Identifying the True Subject
To determine agreement, ignore prepositional phrases and modifiers and focus on the main noun.
Example:
The list of participants is complete.
Subject → list
Verb → is
4. Rule Table
Subjects Followed by Prepositional Phrases
| Structure | Example |
|---|---|
| subject + of phrase | The results of the experiment are accurate. |
| subject + with phrase | The researcher with several assistants is analysing the data. |
The verb agrees with the main subject, not the phrase.
“A Number of” vs “The Number of”
| Expression | Verb Form | Example |
|---|---|---|
| a number of | plural | A number of researchers are analysing the results. |
| the number of | singular | The number of participants is increasing. |
Expressions of Quantity
| Expression | Example |
|---|---|
| a lot of | A lot of data are available. |
| plenty of | Plenty of samples are available. |
| a great deal of | A great deal of research is required. |
Agreement depends on whether the noun is countable or uncountable.
Measurement Expressions
| Expression | Example |
|---|---|
| distance | Ten kilometres is a long distance. |
| time | Five years is a long research period. |
| money | Twenty dollars is sufficient. |
These expressions usually take singular verbs when treated as a single quantity.
5. Usage
1. Subject with prepositional phrase
Example:
The results of the experiment are significant.
2. Agreement with “a number of”
Example:
A number of scientists are investigating the problem.
3. Agreement with “the number of”
Example:
The number of participants is increasing.
4. Agreement with quantities
Example:
A lot of experiments are conducted each year.
5. Agreement with measurements
Example:
Ten kilometres is a long distance for a field survey.
6. Signal Words
Certain expressions often appear in complex subject structures.
| Expression | Example |
|---|---|
| of | The results of the study are reliable. |
| with | The researcher with several assistants is conducting the experiment. |
| along with | The technician along with the engineers is reviewing the equipment. |
| in addition to | The manager in addition to the staff is attending the meeting. |
| together with | The scientist together with the research team is presenting the results. |
These phrases do not change the number of the subject.
7. Special Cases
Subjects with “Along With / Together With”
These expressions do not create compound subjects.
Example:
The researcher along with the assistants is analysing the data.
The subject is researcher, not assistants.
Fractions and Percentages
Agreement depends on the noun that follows.
Example:
Fifty percent of the samples are contaminated.
Fifty percent of the equipment is faulty.
8. Additional Notes
Complex noun phrases often contain relative clauses.
Example:
The researcher who conducted the experiment is presenting the results.
Even though the clause contains another verb, the main subject remains researcher, so the verb must be singular.
Correct subject identification is the key to correct agreement.
9. Common Errors
⚠ Confusing noun inside phrase with subject
Incorrect:
The results of the experiment is accurate.
Correct:
The results of the experiment are accurate.
Explanation:
The subject is results, not experiment.
⚠ Incorrect agreement with “a number of”
Incorrect:
A number of researchers is studying the issue.
Correct:
A number of researchers are studying the issue.
Explanation:
A number of takes a plural verb.
⚠ Incorrect agreement with “the number of”
Incorrect:
The number of participants are increasing.
Correct:
The number of participants is increasing.
Explanation:
The number of takes a singular verb.
⚠ Misinterpreting quantity expressions
Incorrect:
A lot of information are missing.
Correct:
A lot of information is missing.
Explanation:
Information is uncountable.
⚠ Treating modifiers as compound subjects
Incorrect:
The researcher along with the assistants are analysing the samples.
Correct:
The researcher along with the assistants is analysing the samples.
Explanation:
The true subject is researcher.
10. Lesson Mastery
After completing this lesson, you should now be able to:
✅ identify the true subject in complex noun phrases
✅ apply agreement rules when subjects include prepositional phrases
✅ distinguish between a number of and the number of
✅ apply agreement rules with quantities and measurements