
Relative Clauses
A relative clause is extra information added to a sentence to describe a noun. Think of it as a descriptive sticker you attach to a person, place, or thing. These clauses are introduced by relative pronouns like who, which, and that.
Subject Relative Clauses
In these clauses, the relative pronoun (who/which/that) is the subject of the verb that follows it. The pronoun is doing the action.
- Formula:
... noun + who/which/that + verb ...
- Example 1: The man who lives next door is very friendly.
- (Who is doing the action? The man -> who. Who lives? He lives.)
- Example 2: I have a phone which takes amazing pictures.
- (What is doing the action? The phone -> which. Which takes? It takes.)
Rule: In a subject relative clause, you CANNOT omit the relative pronoun.
Incorrect: “The man ~~lives~~ next door is very friendly.”
Object Relative Clauses
In these clauses, the relative pronoun (who/which/that) is the object of the verb. There is a different subject doing the action.
- Formula:
...noun + who/which/that + new subject + verb ...
- Example 1: The man who I met yesterday is very friendly.
- (Who is doing the action? I am. I met the man -> who.)
- Example 2: The phone which you bought looks expensive.
- (Who is doing the action? You are. You bought the phone -> which.)
Rule: In an object relative clause, you CAN omit the relative pronoun. This is very common in spoken English.
Correct: “The phone you bought looks expensive.”
Correct: “The man I met yesterday is very friendly.”
When Can I Omit the Pronoun? 🤔
This is the key takeaway:
If the pronoun is followed by a VERB (it’s a subject clause) -> DO NOT OMIT.
The dog that is barking is my neighbor's.
If the pronoun is followed by a NOUN or PRONOUN (it’s an object clause) -> YOU CAN OMIT.
The dog (that) we saw yesterday was a golden retriever.
Other Useful Pronouns
These pronouns add specific types of information and are generally not omitted in B1-level English.
- Whose (Possession): Used to show that something belongs to someone.
- She’s the artist whose paintings are famous all over the world.”
- Where (Place): Used to describe a location.
- Itagüí is the city where I live.
- When (Time): Used to describe a time.
- 2025 is the year when we will travel to Japan.

Defining and Non-defining Relative Clauses
Learn how to give additional information about people and things using relative clauses. Understanding the difference between these clauses is crucial – one gives essential information needed to identify someone/something, while the other just adds extra details.
⏰ When Do We Use These Clauses?
Defining Relative Clauses (No Commas):
To give essential information that identifies the person/thing
- The doctor who works at the city hospital is my cousin.
- Engineers that design buildings must be very precise.
Non-defining Relative Clauses (With Commas):
To give extra information that isn’t essential
- Dr. Smith, who has worked here for 20 years, is retiring.
- My sister, who is a lawyer, lives in London.
📌 Structure
Defining Clauses:
Who/That/Which + essential information
No commas
The teacher who speaks five languages works here.
Non-defining Clauses:
Comma(,) + Who/Which (never 'that') + extra information + Comma(,)
Use commas
My boss, who started the company, is retiring soon.
Common Relative Pronouns
For People:
- Who (defining and non-defining)
- That (only defining)
- Whom (formal, for objects)
For Things:
- Which (defining and non-defining)
- That (only defining)
📝 Notes
Common Mistakes:
- My uncle, that is a doctor, lives nearby.
- My uncle, who is a doctor, lives nearby.
- The dentist which I visited was excellent.
- The dentist who I visited was excellent.
Important Tips:
- Always use commas with non-defining clauses
- If removing the clause changes the meaning → Defining
- If removing the clause doesn’t change the meaning → Non-defining
- Never use ‘that’ in non-defining clauses
💬 Examples
Defining Clauses (Essential Information):
- The nurses who work in emergency care need special training.
- Teachers that work with young children need lots of patience.
- The chef who won the competition trained in Paris.
Non-defining Clauses (Extra Information):
- My brother, who is a successful architect, designed this building.
- Dr. Johnson, who graduated from Harvard, runs the department.
- The new manager, who moved here from Spain, starts next week.