1. Lesson Overview
In this lesson, you will learn how relative clauses modify nouns and how they can be transformed into more concise grammatical structures.
Relative clauses allow writers to add additional information about a noun without creating a separate sentence. They help combine ideas smoothly and produce clear, cohesive sentences.
Example:
Simple sentences:
The scientist conducted the experiment.
The scientist published the results.
Combined sentence:
The scientist who conducted the experiment published the results.
Relative clauses therefore help writers connect information efficiently while maintaining clarity.
By the end of this lesson, you will be able to:
-
understand how relative clauses modify nouns
-
use relative pronouns such as who, whom, whose, which, and that
-
transform or reduce relative clauses into shorter structures
-
identify and correct common errors involving relative clause structures
2. Concept Introduction
Consider the following example.
Simple sentences:
The laboratory is well equipped.
The laboratory conducts advanced research.
Combined sentence:
The laboratory that conducts advanced research is well equipped.
| Clause Type | Example |
|---|---|
| relative clause | that conducts advanced research |
| main clause | The laboratory is well equipped |
The relative clause provides additional information about the noun.
3. Core Explanation
A relative clause is a dependent clause that modifies a noun or noun phrase.
Relative clauses usually begin with relative pronouns.
Common relative pronouns include:
who
whom
whose
which
that
Example:
The researcher who analysed the data published the findings.
The clause who analysed the data modifies the noun researcher.
Defining vs Non-Defining Relative Clauses
Relative clauses can be classified into two types.
Defining relative clauses
These clauses provide essential information.
Example:
The scientist who developed the theory won an award.
Without the clause, the meaning would be unclear.
Non-defining relative clauses
These clauses provide additional information.
Example:
The scientist, who developed the theory, won an award.
Non-defining clauses are usually separated by commas.
4. Rule Table
Relative Pronouns and Their Functions
| Relative Pronoun | Function | Example |
|---|---|---|
| who | refers to people | The scientist who conducted the experiment published the results. |
| whom | object form for people | The researcher whom the committee selected presented the findings. |
| whose | possession | The engineer whose design improved the system received recognition. |
| which | refers to things | The device which measures temperature is highly accurate. |
| that | refers to people or things (defining clauses) | The equipment that failed was replaced immediately. |
5. Usage
Relative clauses allow writers to combine sentences effectively.
1. Identifying people
Example:
The technician who repaired the system received praise.
2. Identifying objects
Example:
The instrument that measures pressure is extremely sensitive.
3. Showing possession
Example:
The scientist whose research influenced the field received an award.
4. Adding descriptive information
Example:
The laboratory, which was recently renovated, now contains advanced equipment.
5. Clarifying specific nouns
Example:
The experiment that produced unexpected results was repeated.
6. Signal Words
Relative clauses usually begin with relative pronouns.
| Relative Word | Example |
|---|---|
| who | The researcher who analysed the data published the results. |
| whom | The scientist whom the committee recognised received an award. |
| whose | The engineer whose design improved the system gained recognition. |
| which | The machine which processes the samples is highly efficient. |
| that | The project that required extensive analysis was completed successfully. |
These words introduce clauses that modify nouns.
7. Special Cases
Omitting the Relative Pronoun
Sometimes the relative pronoun can be omitted when it functions as the object of the clause.
Example:
Full sentence:
The report that the researcher wrote was published.
Reduced sentence:
The report the researcher wrote was published.
Using “That” Instead of “Which” or “Who”
In defining relative clauses, that may replace who or which.
Example:
The device that measures pressure is extremely accurate.
8. Additional Notes
Relative clauses can sometimes be reduced to participle phrases.
Example:
Original sentence:
The researchers who analysed the data discovered the error.
Reduced form:
The researchers analysing the data discovered the error.
Such reductions make sentences shorter and more concise, which is common in academic writing.
9. Common Errors
⚠ Incorrect relative pronoun
Incorrect:
The scientist which discovered the formula received an award.
Correct:
The scientist who discovered the formula received an award.
Explanation:
Who refers to people.
⚠ Missing relative pronoun
Incorrect:
The device measures pressure is highly accurate.
Correct:
The device that measures pressure is highly accurate.
Explanation:
The clause requires a relative pronoun.
⚠ Incorrect punctuation
Incorrect:
The laboratory which was renovated recently now contains advanced equipment.
Correct:
The laboratory, which was renovated recently, now contains advanced equipment.
Explanation:
Non-defining clauses require commas.
⚠ Incorrect verb agreement
Incorrect:
The scientist who study the results publishes the report.
Correct:
The scientist who studies the results publishes the report.
Explanation:
The verb must agree with the antecedent noun.
⚠ Ambiguous reference
Incorrect:
The researcher spoke to the technician who was concerned.
Correct:
The researcher spoke to the technician, who was concerned about the equipment.
Explanation:
Relative clauses must clearly identify the noun they modify.
10. Lesson Mastery
After completing this lesson, you should now be able to:
✅ understand how relative clauses modify nouns
✅ use relative pronouns such as who, whom, whose, which, and that
✅ transform or reduce relative clauses into concise structures
✅ identify and correct errors involving relative clauses