English course · Unit 29

Relative Clauses

Who, which, that, whose — and the meaning of commas

How to use this unit

Read each short text before answering the questions. A defining relative clause identifies the person or thing we mean. A non-defining relative clause adds extra information about someone or something already identified.

Defining: The nurse who works at night lives nearby. (Which nurse?)

Non-defining: Mrs Patel, who works at night, lives nearby. (We already know who Mrs Patel is.)

In the gap exercises, you may enter the missing words or the complete sentence. In punctuation exercises, enter the whole sentence, including commas where needed. The checker accepts appropriate alternatives. Show answers always displays complete model sentences.

Important: A comma is not just a pause. It can change whether a relative clause identifies someone or adds information. Each punctuation question supplies the context needed to decide.

Step 1

Finding the person or thing

At a community centre, three volunteers are preparing an exhibition. The woman who organises the photographs is called Aisha. The man whose camera was damaged is called Ben. The pictures that show the old railway station are particularly popular.

These relative clauses identify people and things. No commas are needed. Who refers to people, which to things, that to people or things in defining clauses, and whose expresses possession.

Complete each sentence with a suitable relative word.

1. The woman ______ organises the photographs is called Aisha.

Complete the gap (or write the whole sentence).

2. The photographs ______ show the old station are popular.

Complete the gap (or write the whole sentence).

3. The man ______ camera was damaged is called Ben.

Complete the gap (or write the whole sentence).

4. The volunteers ______ arrived early helped arrange the chairs.

Complete the gap (or write the whole sentence).

Complete model answers

The woman who organises the photographs is called Aisha.
The photographs that show the old station are popular.
The man whose camera was damaged is called Ben.
The volunteers who arrived early helped arrange the chairs.

Step 2

When commas change the meaning

Two brothers: Sam has two brothers. One lives in Bristol and one lives in York. His brother who lives in Bristol is a teacher.

One brother: Nina has only one brother. Her brother, who lives in Bristol, is a teacher.

A named place: The Royal Pavilion, which is in Brighton, attracts visitors.

A defining clause answers Which one? and has no commas. A non-defining clause gives extra information and is separated by commas (or by a single comma at the end of the sentence).

Rewrite each complete sentence, inserting commas only where they are needed. Do not change the words.

1. Maya has one sister. Punctuate: My sister who lives in Leeds is a nurse.

Write the complete sentence, including punctuation.

2. David has three sisters. Identify the one in Leeds: My sister who lives in Leeds is a nurse.

Write the complete sentence, including punctuation.

3. Punctuate: Brighton which is on the south coast of England is a popular seaside city.

Write the complete sentence, including punctuation.

4. There are several books on the table. Identify the red one: The book that has a red cover belongs to Leo.

Write the complete sentence, including punctuation.

5. Punctuate: My father whose birthday is tomorrow is coming to dinner. (The speaker is referring to their already identified father.)

Write the complete sentence, including punctuation.

Complete model answers

My sister, who lives in Leeds, is a nurse.
My sister who lives in Leeds is a nurse.
Brighton, which is on the south coast of England, is a popular seaside city.
The book that has a red cover belongs to Leo.
My father, whose birthday is tomorrow, is coming to dinner.

Step 3

That, which and the missing pronoun

A customer is describing a lost bag: “The bag that I left on the train was blue. The passenger who found it handed it to the guard. The guard who I spoke to was very helpful.”

In a defining clause, we can often omit a relative pronoun when it is the object: The bag (that) I left … But we cannot omit the pronoun when it is the subject: The passenger who found it …

Complete the gaps. Some answers can be left empty: for these, write “omit”.

1. The bag ______ I left on the train was blue. (Write a pronoun or “omit”.)

Complete the gap (or write the whole sentence).

2. The passenger ______ found it handed it to the guard.

Complete the gap (or write the whole sentence).

3. The guard ______ I spoke to was very helpful. (Write a pronoun or “omit”.)

Complete the gap (or write the whole sentence).

4. The bag, ______ was blue, was returned to me.

Complete the gap (or write the whole sentence).

Complete model answers

The bag that I left on the train was blue.
The passenger who found it handed it to the guard.
The guard who I spoke to was very helpful.
The bag, which was blue, was returned to me.

Step 4

An exhibition: information and punctuation

The community centre is displaying photographs of the neighbourhood. There are many photographs, but only some show the old railway station. The organiser, Aisha, has worked on the exhibition for several months. Ben, whose grandfather took several of the photographs, is giving a short talk.

Combine the information as instructed. Type the complete sentence, including commas where necessary.

1. Several photographs show the old station. Those photographs were taken in 1960. Begin: “The photographs …” (Identify which photographs.)

Write the complete sentence, including punctuation.

2. Aisha has organised the exhibition. She has worked on it for months. Begin: “Aisha …” (Add extra information.)

Write the complete sentence, including punctuation.

3. Ben is giving a talk. His grandfather took several photographs. Begin: “Ben …”

Write the complete sentence, including punctuation.

4. The railway station was demolished in 1982. It stood near the park. Begin: “The railway station …” (The station is already identified.)

Write the complete sentence, including punctuation.

Complete model answers

The photographs that show the old station were taken in 1960.
Aisha, who has worked on the exhibition for months, has organised the exhibition.
Ben, whose grandfather took several of the photographs, is giving a talk.
The railway station, which stood near the park, was demolished in 1982.

Step 5

A medical report: revisiting the passive

Nurse: The patient who arrived yesterday is recovering well. The medication that was prescribed by the doctor has been administered. Mr Harris, whose blood pressure was monitored overnight, is comfortable. His test results, which were received this morning, have been added to his notes.

Notice the relative clauses alongside the past simple passive and present perfect passive. The pronoun does not determine the tense; the time and meaning do.

Complete the sentences using the relative word shown by the context.

1. The patient ______ arrived yesterday is recovering well.

Complete the gap (or write the whole sentence).

2. The medication ______ was prescribed has been administered.

Complete the gap (or write the whole sentence).

3. Mr Harris, ______ blood pressure was monitored overnight, is comfortable.

Complete the gap (or write the whole sentence).

4. His test results, ______ were received this morning, have been added to his notes.

Complete the gap (or write the whole sentence).

Complete model answers

The patient who arrived yesterday is recovering well.
The medication that was prescribed has been administered.
Mr Harris, whose blood pressure was monitored overnight, is comfortable.
His test results, which were received this morning, have been added to his notes.

Step 6

Scientific English: describing an experiment

In a classroom experiment, two identical containers were used. The container that was placed near the window became warmer. The second container, which was kept in a cupboard, remained cooler. The students, whose measurements were recorded every ten minutes, compared their results at the end.

Scientific writing often uses relative clauses to identify equipment and add details about procedures. It also provides a natural setting for the passive.

Rewrite the sentences with the correct commas, keeping all the words unchanged.

1. Two containers were used. Identify the one by the window: The container that was placed near the window became warmer.

Write the complete sentence, including punctuation.

2. The second container is already identified. Punctuate: The second container which was kept in a cupboard remained cooler.

Write the complete sentence, including punctuation.

3. The students are already identified. Punctuate: The students whose measurements were recorded every ten minutes compared their results.

Write the complete sentence, including punctuation.

4. There are several thermometers. Identify the one with a broken display: The thermometer that had a broken display was replaced.

Write the complete sentence, including punctuation.

Complete model answers

The container that was placed near the window became warmer.
The second container, which was kept in a cupboard, remained cooler.
The students, whose measurements were recorded every ten minutes, compared their results.
The thermometer that had a broken display was replaced.

Step 7

Final review: meaning, tenses and commas

In this final step, decide whether the clause identifies someone or something, or merely adds information. Pay attention to the verb forms you have already learnt.

Write each complete sentence with the correct punctuation and relative pronoun. Follow the instructions exactly.

1. Use WHO: Dr Evans is already identified. She treated the patient yesterday. Combine: “Dr Evans … has retired.”

Write the complete sentence, including punctuation.

2. Use WHOSE: There are several nurses. Identify the nurse whose bicycle was stolen. Complete: “The nurse … has reported it to the police.”

Write the complete sentence, including punctuation.

3. Use WHICH: The bridge is already identified. It was built in 1890. Complete: “The bridge … has recently been restored.”

Write the complete sentence, including punctuation.

4. Use THAT: Several trains leave from platform 3. Identify the train leaving at 8.15. Complete: “The train … is delayed.”

Write the complete sentence, including punctuation.

5. Use WHICH: Brighton is already identified. It is on the south coast. Complete: “Brighton … attracts many visitors.”

Write the complete sentence, including punctuation.

Complete model answers

Dr Evans, who treated the patient yesterday, has retired.
The nurse whose bicycle was stolen has reported it to the police.
The bridge, which was built in 1890, has recently been restored.
The train that leaves at 8.15 is delayed.
Brighton, which is on the south coast, attracts many visitors.

What you have learnt

You can now use who, which, that and whose, distinguish identifying information from additional information, and punctuate relative clauses accordingly. You have also revised the present simple, past simple, present perfect and passive voice.

Remember: in real writing, context determines whether a relative clause is defining or non-defining. If both readings are possible, punctuation may change the meaning rather than simply being right or wrong.