Relative Clauses | Intermediate English for IELTS

Intermediate English for IELTS: Relative Clauses

Relative clauses are one of the most important grammar topics for IELTS because they help you add detail, combine ideas, and write or speak more naturally. Instead of using many short sentences, you can connect information smoothly and make your English sound more advanced.

Before studying this lesson, it is useful to understand Sentence Structure Basics, Parts of Speech, Pronouns for IELTS, Articles in English, Present Simple Tense, Past Simple Tense, Past Perfect Tense, and Passive Voice. These lessons will help you understand how relative clauses fit into real sentences.

What are relative clauses?

A relative clause is a clause that gives extra information about a noun. It usually begins with a relative pronoun or relative adverb such as who, which, that, whose, where, when, or why.

Example:

• The teacher who helped me was very kind.

Here, the relative clause who helped me gives more information about the teacher.

Relative clauses are useful because they help you:

• describe people, things, places, and times
• avoid repeating words
• make sentences more complex and natural
• improve grammar range in IELTS Writing and Speaking

Why relative clauses matter for IELTS

Relative clauses are very helpful in all parts of IELTS.

In Writing, they help you:

• combine ideas clearly
• add detail without making sentences awkward
• show a wider grammatical range
• make descriptions more precise

In Speaking, they help you:

• describe people, places, and experiences more naturally
• give fuller answers
• sound less repetitive
• improve fluency and coherence

For example, instead of saying:

• I met a man. He works in a hospital.

you can say:

• I met a man who works in a hospital.

That is smoother, shorter, and more natural.

The two main types of relative clauses

There are two main types:

1. Defining relative clauses
2. Non-defining relative clauses

1) Defining relative clauses

Defining relative clauses give essential information. They tell us exactly which person or thing we are talking about.

Example:

• The woman who lives next door is a doctor.

Without the clause, we would not know which woman you mean.

Common features of defining relative clauses

• no commas are used
• the information is necessary
• that can often be used
• the relative pronoun can sometimes be omitted when it is the object

Examples:

• I know the student who won the prize.
• This is the book that I borrowed.
• The film I watched yesterday was excellent.

2) Non-defining relative clauses

Non-defining relative clauses give extra information that is not essential. The sentence still makes sense without them.

Example:

• My brother, who lives in London, is a pilot.

If you remove the clause, the main meaning is still clear:

• My brother is a pilot.

Common features of non-defining relative clauses

• commas are used
• the information is extra, not essential
• that is not used
• the relative pronoun cannot usually be omitted

Examples:

• My car, which I bought last year, is already showing problems.
• Istanbul, where I studied for two years, is a busy city.
• My aunt, who is an excellent cook, taught me this recipe.

Relative pronouns and relative adverbs

Relative clauses usually begin with one of these words.

1) Who

Use who for people.

• The man who called you is my uncle.
• The students who studied hard passed the test.

2) Whom

Use whom mainly in formal English for people when it is the object of the clause.

• The woman whom I met was very polite.

In everyday English, many speakers use who instead of whom, or leave the pronoun out when possible.

3) Which

Use which for things and animals.

• The phone which I bought is very fast.
• The dog which lives next door is very friendly.

4) That

Use that for people or things in defining relative clauses.

• The book that I read was useful.
• The girl that won the race is my cousin.

Important: do not use that in non-defining relative clauses.

5) Whose

Use whose to show possession.

• The student whose essay was excellent received praise.
• I met a family whose house was damaged by the storm.

6) Where

Use where for places.

• This is the café where we met.
• The town where I grew up is small.

7) When

Use when for times.

• I remember the day when we first met.
• That was the year when I started university.

8) Why

Use why for reasons.

• I do not know the reason why she left early.
• There is no clear explanation why the system failed.

Defining vs. non-defining: the key differences

Defining relative clauses

• essential information
• no commas
• can use that
• pronoun may be omitted if it is the object

Example:

• The book that you recommended was excellent.

Non-defining relative clauses

• extra information
• commas required
• cannot use that
• pronoun usually cannot be omitted

Example:

• My sister, who lives in Canada, is visiting next month.

A simple test is this: if the clause helps identify the noun, it is probably defining. If it only adds extra information, it is probably non-defining.

When can the relative pronoun be omitted?

You can often omit the relative pronoun in defining relative clauses when it is the object of the clause.

With pronoun

• The movie that I saw was fantastic.

Without pronoun

• The movie I saw was fantastic.

You cannot omit it when it is the subject

• The woman who works here is very helpful.
• Not: The woman works here is very helpful.

This rule is very useful in IELTS because it helps you write more naturally without repeating too many unnecessary words.

Relative clauses with prepositions

Sometimes a preposition appears in the relative clause.

Informal style: preposition at the end

• The person who I spoke to was helpful.
• The house which they moved into is old.

More formal style: preposition before the relative pronoun

• The person to whom I spoke was helpful.
• The house into which they moved is old.

For IELTS, both forms are correct, but the first form is more natural in everyday speaking. The second form sounds more formal and is useful in writing.

Relative clauses with reduced forms

In more advanced English, relative clauses can sometimes be reduced.

With a relative clause

• The girl who is sitting near the window is my classmate.

Reduced form

• The girl sitting near the window is my classmate.

This is common when the relative clause uses be or when the clause is very clear from context.

Reduced relative clauses are useful in IELTS Writing because they help create more compact and sophisticated sentences.

Relative clauses in academic and IELTS writing

Relative clauses are especially helpful when you want to describe data, people, or situations clearly.

In IELTS Writing Task 1

• The graph shows the number of students who enrolled in online courses.
• The city, which experienced rapid growth, saw a rise in traffic.

In IELTS Writing Task 2

• People who work long hours often have less time for exercise.
• The government should support businesses that create sustainable jobs.
• Cities where public transport is reliable usually have less congestion.

Relative clauses help you write with more precision and less repetition, which improves clarity and cohesion.

Relative clauses in IELTS Speaking

In speaking, relative clauses can make your answers sound more natural and complete.

Example answers

• My favourite teacher was someone who always encouraged us.
• I live in a neighbourhood where there are many parks.
• One book that I really enjoyed was about history.

Better than short, repeated sentences

Instead of:

• I visited a museum. It was very interesting. It had many old objects.

you can say:

• I visited a museum that had many old objects, and it was very interesting.

Common mistakes with relative clauses

Mistake 1: Using the wrong relative pronoun

Incorrect:

• The woman which lives next door is kind.

Correct:

• The woman who lives next door is kind.

Mistake 2: Using “that” in a non-defining clause

Incorrect:

• My brother, that lives in Dubai, is coming home.

Correct:

• My brother, who lives in Dubai, is coming home.

Mistake 3: Forgetting commas in non-defining clauses

Incorrect:

• My laptop which I bought last year is already slow.

Correct:

• My laptop, which I bought last year, is already slow.

Mistake 4: Omitting the pronoun when it is the subject

Incorrect:

• The man works here is my uncle.

Correct:

• The man who works here is my uncle.

Mistake 5: Confusing defining and non-defining meaning

Incorrect:

• My sister who lives in Karachi is a doctor.
  If you have only one sister, commas may be needed depending on the meaning.

Correct:

• My sister, who lives in Karachi, is a doctor.
  This suggests you already know which sister you mean.

Mistake 6: Using awkward sentence order

Incorrect:

• I met a boy was very friendly.

Correct:

• I met a boy who was very friendly.

Mistake 7: Overusing relative clauses

Too many relative clauses can make a sentence heavy and unclear. Use them to improve meaning, not just to make sentences longer.

For balance, combine them with Adjectives, Adverbs, Comparatives and Superlatives, and Prepositions in English when describing ideas.

Useful Tips for IELTS Students

• Learn the difference between defining and non-defining clauses first.
• Remember that commas matter.
• Use who for people and which for things.
• Use that only in defining clauses.
• Try to omit the relative pronoun only when it is the object and the sentence still stays clear.
• Practice combining two simple sentences into one strong complex sentence.
• Review Pronouns for IELTS and Subject-Verb Agreement so your relative clauses stay grammatically correct.

Practice: Relative clauses

Exercise 1: Join the sentences

Combine each pair using a relative clause.

1. I know a girl. She speaks four languages.
2. This is the restaurant. We had dinner there last night.
3. The book is on the table. It belongs to me.
4. My uncle is a doctor. He lives in London.
5. I met a student. Her father is a pilot.

Exercise 2: Choose the correct relative pronoun

1. The man ___ helped me was very polite.
2. The city ___ I was born is very crowded.
3. My friend, ___ lives in Canada, is coming to visit.
4. The company ___ I work for is expanding.
5. The reason ___ he left is unclear.

Exercise 3: Defining or non-defining?

Write D for defining and N for non-defining.

1. The students who passed the test were happy.
2. My laptop, which is very old, still works well.
3. The café where we met is closed now.
4. Mr Khan, who teaches history, is very popular.
5. The time when we arrived was perfect.

Answer key

Exercise 1 sample answers

1. I know a girl who speaks four languages.
2. This is the restaurant where we had dinner last night.
3. The book that is on the table belongs to me.
4. My uncle, who lives in London, is a doctor.
5. I met a student whose father is a pilot.

Exercise 2 answers

1. who / that
2. where
3. who
4. that / which
5. why

Exercise 3 answers

1. D
2. N
3. D
4. N
5. D

Frequently Asked Questions

1) What is a relative clause?

A relative clause is a clause that adds information about a noun in the main clause.

2) What are the two main types of relative clauses?

The two main types are defining relative clauses and non-defining relative clauses.

3) What is the difference between who and which?

Use who for people and which for things and animals.

4) Can I use that in every relative clause?

No. That is used in defining relative clauses, but not in non-defining relative clauses.

5) Do non-defining relative clauses need commas?

Yes. They are separated by commas.

6) Can I leave out the relative pronoun?

Yes, sometimes, but only in defining relative clauses when the pronoun is the object, not the subject.

7) Are relative clauses useful in IELTS Writing Task 2?

Yes. They help you combine ideas, reduce repetition, and show grammar variety.

8) Are relative clauses useful in IELTS Speaking?

Yes. They help you give fuller, smoother answers with better sentence variety.

9) What is a reduced relative clause?

It is a shorter form of a relative clause, often used in more advanced English to make sentences more compact.

10) What is the easiest way to practise relative clauses?

Start by joining two short sentences into one sentence using who, which, that, whose, where, when, or why.

Relative Clauses in English for IELTS

Relative clauses help you add detail, connect ideas, and speak or write with more precision. They are especially valuable in IELTS because they improve sentence complexity without making your English sound unnatural. Start with the difference between defining and non-defining clauses, learn the common relative pronouns, and practise turning short sentences into one strong sentence.

To continue building strong grammar for IELTS, review Sentence Structure Basics, Parts of Speech, Pronouns for IELTS, Articles in English, Passive Voice, and Reported Speech.