What is a restrictive relative clause?
A relative clause is a small sentence inside a bigger sentence that tells us more about a noun. A restrictive (also called defining) relative clause tells us which person or thing we mean. Without it the sentence would not be clear.
Example: The scientist who discovered penicillin was Alexander Fleming. There were many scientists, so 'who discovered penicillin' tells us exactly which one.
Rules:
- No commas around a restrictive clause.
- The clause comes right after the noun it describes.
- The clause has a verb of its own.
Who, that and which
The words that start a relative clause are relative pronouns.
- who: for people. The doctor who treated her was kind.
- that: for people or things. The experiment that failed taught her a lot.
- which: for things. The lab which she built is now a museum.
When the pronoun is the object of the clause, you may drop it: The book (that) I read was about Marie Curie. When it is the subject, you must keep it: The book that changed my mind...
Reading stories of people of achievement
Biographies of scientists often follow a pattern. Look for these five parts when you read:
- Curiosity: a question the person could not stop asking.
- Hard work: long hours, small steps, many tries.
- Setbacks: lack of money, failed experiments, people who doubted them.
- Discovery: the moment the answer appears.
- Effect on the world: how the discovery helped others.
Examples to read about: Marie Curie, who studied radioactivity and won two Nobel Prizes (1903 in Physics, 1911 in Chemistry); C. V. Raman, who explained how light scatters in a substance (the Raman effect, 1928) and won the Nobel Prize in 1930; Tu Youyou, who found artemisinin, a medicine for malaria, and won the Nobel Prize in 2015; Alexander Fleming, who noticed that mould killed bacteria (1928).
Notice: each of those sentences used a restrictive clause to say which achievement.
Putting the two together: writing about a hero
When you write a short biography, use restrictive clauses to pack facts in one sentence: Tu Youyou is the scientist who found a medicine that saves millions of lives from malaria. Two clauses (who found..., that saves...), one smooth sentence.
Tip: do not use more than two clauses in a sentence, or the reader gets lost.
Try it: one-sentence heroes
Do this in 10 minutes. Choose three people you admire (a scientist, a teacher, a family member). For each, write one sentence with who and one with that. Example: My aunt is the nurse who stayed all night; she gave the medicine that lowered his fever. Underline each clause. Cover the clause: is the sentence still clear? If not, it is restrictive. Then use the 3D to practise: pick a hat and a tool and see how the clause narrows the crowd.
Key formulas and definitions
- Noun + who + verb... (person)
- Noun + that / which + verb... (thing)
- Restrictive clause: no commas, needed to know which one
- Object pronoun may be dropped; subject pronoun must stay
- Biography = curiosity + hard work + setbacks + discovery + effect
Worked examples
1. Join the sentences with who: 'The teacher helped me. She taught chemistry.'
The teacher who taught chemistry helped me.
2. Fill in who, that or which: 'The medicine ___ she found saves lives.'
That (or which). 'Medicine' is a thing: 'The medicine that she found saves lives.'
3. Which sentence has a restrictive clause? (a) My brother, who is ten, plays chess. (b) The boy who plays chess is my brother.
(b). 'who plays chess' tells which boy. In (a) the clause is extra information between commas.
4. Can you drop the pronoun? 'The book that I read was long.'
Yes. 'that' is the object of 'read', so 'The book I read was long.' is correct.
5. Can you drop the pronoun? 'The scientist who won the prize was happy.'
No. 'who' is the subject of 'won'. Without it the sentence is wrong.
6. Write one sentence about Marie Curie using a restrictive clause.
Marie Curie is the scientist who won Nobel Prizes in two different sciences.
Common mistakes
- Putting commas around a restrictive clause. If the clause is needed to know which one, no commas.
- Using which for people. Say 'the girl who...', not 'the girl which...'.
- Dropping a subject pronoun: 'The man won the prize was happy' is wrong; keep 'who'.
- Using that after a comma. Use 'which' with commas for extra information, not 'that'.