What Are Reduced Relative Clauses?
A reduced relative clause is a shorter way to write a relative clause. Instead of using the full relative clause with a relative pronoun (who, which, that) and a verb, we remove these words to make the sentence simpler and more concise. Reduced relative clauses are very common in English, especially in writing and formal speech. They help us communicate more efficiently without changing the meaning of the sentence.
How to Form Reduced Relative Clauses
There are two main ways to reduce a relative clause. First, you can remove the relative pronoun (who, which, that) and the auxiliary verb (is, are, was, were) when you have a continuous form. For example: 'The woman standing in the corner is my teacher' comes from 'The woman who is standing in the corner is my teacher.' Second, you can remove the relative pronoun and use the past participle when describing something that happened before. For example: 'The letter sent yesterday was important' comes from 'The letter that was sent yesterday was important.'
When to Use Reduced Relative Clauses
Reduced relative clauses are most useful when you want to make your writing more natural and easier to read. You can use them in formal writing like essays and reports, or in casual conversation. However, not all relative clauses can be reduced. You must be able to remove the relative pronoun and auxiliary verb without losing the meaning. If the sentence becomes confusing or unclear after reduction, keep the full relative clause instead.
Full vs. Reduced Relative Clauses: Side-by-Side Comparison
| Category | Full Relative Clause | Reduced Relative Clause |
|---|---|---|
| Form (Active) | Noun + who/that/which + is/are/was/were + present participle (-ing) e.g. who/that is running |
Noun + present participle (-ing) Remove the relative pronoun and auxiliary verb. e.g. running |
| Form (Passive) | Noun + who/that/which + is/are/was/were + past participle (-ed) e.g. which was built |
Noun + past participle (-ed) Remove the relative pronoun and be auxiliary verb. e.g. built |
| When to Use | Used in all registers — formal and informal — to add descriptive information about a noun using a full clause with a subject and verb. | Used when the subject of the relative clause is the same as the noun being modified. Common in formal writing and academic English to create concise, fluent prose. |
| Positive Example (Active) | The man who is sitting by the window is my uncle. The students who were waiting in the hall looked nervous. |
The man sitting by the window is my uncle. The students waiting in the hall looked nervous. |
| Positive Example (Passive) | The bridge that was built in 1920 is still in use. The documents that were signed yesterday are missing. |
The bridge built in 1920 is still in use. The documents signed yesterday are missing. |
| Negative Example | Anyone who does not hold a ticket cannot enter. The package that was not delivered is still at the warehouse. |
Anyone not holding a ticket cannot enter. The package not delivered is still at the warehouse. (Note: Place "not" directly before the participle.) |
| Question Example | Do you know the woman who is talking to the director? Can you find the report that was submitted last week? |
Do you know the woman talking to the director? Can you find the report submitted last week? |
| What Is Removed | Nothing is removed — the relative pronoun (who, that, which) and the auxiliary verb (is, are, was, were) are both present. | Active: Remove relative pronoun + be auxiliary → keep -ing form. Passive: Remove relative pronoun + be auxiliary → keep past participle (-ed/-en). |
| Key Signal Words | who, whom, whose, which, that followed by a conjugated verb form. Examples: who is, which are, that was, who were |
A participle placed directly after the noun with no pronoun or auxiliary. Active signals: -ing words (running, speaking, holding) Passive signals: -ed/-en words (built, written, signed, damaged) |
| Common Mistakes | Using a full clause when the context is formal and a reduced clause would sound more natural and academic. | Forgetting to remove both the pronoun and the auxiliary. Using the reduced form when subjects differ (e.g. the car hit the man walking to the shop — ambiguous). Using -ing for passive meaning (incorrect: the letter writing; correct: the letter written). |
Key Difference: A full relative clause uses a relative pronoun (who, which, that) and an auxiliary verb (is/are/was/were) to introduce descriptive information about a noun. A reduced relative clause removes both the relative pronoun and the auxiliary verb, leaving only the participle — either the present participle (-ing) for active meaning or the past participle (-ed/-en) for passive meaning. Reduction is only possible when the subject of the relative clause is identical to the noun it modifies, and it is preferred in formal and academic writing for conciseness and fluency.
Formula
Formula
Noun
+
(+ present participle)
+
verb
The man waiting for the bus is my father.
Examples
The student studying in the library is preparing for the exam.
Reduced form of 'who is studying' · Continuous action
The book published last month became a bestseller.
Reduced form of 'that was published' · Past action
Children playing outside should come back before sunset.
Reduced form of 'who are playing' · Present continuous
The broken window needs to be repaired.
Reduced form of 'that is broken' · Adjective form
The technology used in this factory is very modern.
Reduced form of 'that is used' · Passive voice
The employees working on this project are very talented.
Reduced form of 'who are working' · Present continuous
When to use it
Academic Writing
Use reduced relative clauses to make essays and reports more concise and professional.
"The research conducted by our team shows positive results."
Business Communication
Make emails and reports clearer by reducing longer clauses and removing unnecessary words.
"The clients requesting additional services will receive a special discount."
Everyday Conversation
Sound more natural when describing people, places, and things in casual speech.
"The guy sitting next to me on the train was very friendly."
News and Media
Journalists use reduced clauses to provide information quickly and efficiently.
"The witness interviewed by police said she saw the suspect at 8 p.m."
Signal words
present participle (-ing)
past participle (-ed, -en)
continuous form
which is
who is
that is
that was
which was
Common Mistakes
✕
Wrong
The students study in the library are preparing for exams.
✓
Correct
The students studying in the library are preparing for exams.
Use the -ing form (present participle), not the base form of the verb.
✕
Wrong
The package deliver yesterday has arrived.
✓
Correct
The package delivered yesterday has arrived.
Use the past participle (-ed), not the base form of the verb.
✕
Wrong
The information provide by the teacher was helpful.
✓
Correct
The information provided by the teacher was helpful.
The past participle 'provided' must agree with the noun being described.
✕
Wrong
The children playing in the park was happy.
✓
Correct
The children playing in the park were happy.
The verb must still agree with the noun in number (plural children = were).
KEY TAKEAWAYS
What to Remember
- Reduced relative clauses shorten sentences by removing the relative pronoun and auxiliary verb.
- You can reduce clauses with who/which + be verb by deleting both words.
- Remove only the relative pronoun when the verb is active (not a be-verb).
- Reduced relative clauses are common in writing and formal speech for conciseness.
- The meaning stays the same after reduction; only the structure becomes simpler.