A relative clause is a subordinate clause that modifies a noun — it gives additional information about a person, thing, or place. English has two types: defining relative clauses (which identify exactly which person or thing is meant) and non-defining relative clauses (which add extra information about an already-identified noun). The difference between them is not just grammatical — it changes the meaning. The comma is not just punctuation — it is a meaning signal.
Before you start — think honestly about your own teaching and experience.
Look at the examples. Answer each question before reading the explanation — this is how your students will learn too.
Read these pairs of sentences. Each pair contains a similar idea — but the punctuation and meaning are different. Can you identify how the meaning changes?
Sentence A (defining): 'The teacher who taught me English' — the relative clause is essential. Without it ('The teacher changed my life'), we do not know WHICH teacher. The clause defines exactly which one. This is a DEFINING relative clause. Sentence B (non-defining): 'My English teacher, who has taught for thirty years, is retiring' — 'My English teacher' already identifies the person. The relative clause just adds extra information. Without it ('My English teacher is retiring next month'), the sentence is still perfectly clear. This is a NON-DEFINING relative clause. Defining: essential to the meaning — tells you which one. Non-defining: extra information about something already identified. This meaning distinction is the most important thing to understand about relative clauses — the comma is how we signal it in writing.'
Now look at which relative pronouns are used in these sentences. Can you find the pattern — when is 'who' used? When is 'which'? When is 'that'?
Who = for people. 'The teacher who helped me'. Which = for things and animals. 'The book which changed my life'. That = for both people and things — BUT only in DEFINING relative clauses. 'That' is never used in non-defining relative clauses. Whose = for possession (of people or things). 'The student whose work impressed me'. Where = for places. 'The village where I grew up'. A key practical question: use 'who' for people, 'which' for things, 'that' for either (in defining clauses only). In formal written English, 'who' for people is strongly preferred over 'that'. 'That' is more common in informal speech.'
Now look at these sentences. Some have errors — either the wrong pronoun, a missing comma, or an extra pronoun inside the clause. Can you find and correct each error?
Sentence 1: 'which' should be 'who' — the teacher is a person. 'The teacher who taught me'. Sentence 2: 'that' cannot be used in non-defining relative clauses (commas signal non-defining). Change 'that' to 'which': 'The school, which my children attend, is very well-resourced.' Sentence 3: 'who she appointed' — there is an extra pronoun 'she'. In a relative clause, the relative pronoun replaces the subject or object — do not add another pronoun. 'The director who she appointed' should be 'the director who(m) the director appointed' → 'the director whom/who he appointed last year'. Wait — 'who she appointed' could mean she appointed the director. In that case, 'who' is the object — so 'whom' is technically correct in formal English, but 'who' is widely accepted. The error is 'who she' — the relative pronoun replaces the second noun, not adds to it. Sentence 4: 'My headteacher' is already specific — the non-defining clause needs commas: 'My headteacher, who has worked here for twenty years, is very respected.''
| Tense / Form | Use / Meaning | Example | Key time words |
|---|---|---|---|
| Defining | Identifies which one — essential to meaning | The student who failed the test needs extra support. | No commas — that/who/which |
| Non-defining | Adds extra info about an already-identified noun | Maria, who failed the test, needs extra support. | Commas — who/which only (never that) |
| Who | People | The teacher who inspired me most retired last year. | Both defining and non-defining |
| Which | Things and animals | The textbook which arrived last week is excellent. | Both defining and non-defining |
| That | People or things (informal/spoken) | The book that helped me most is out of print. | ONLY in defining clauses |
| Whose | Possession (people or things) | The student whose work was outstanding won the prize. | Both types |
| Where | Places | The village where she grew up has no clinic. | Both types |
THE COMMA IS A MEANING SIGNAL — not just punctuation:
In relative clauses, the comma does something important — it signals the TYPE of relative clause, which changes the MEANING.
NO COMMAS (defining):
'The teachers who work here are very dedicated.' = Not all teachers — only the ones who work HERE are dedicated. (Implies there are other teachers who are not dedicated.)
COMMAD (non-defining):
'The teachers, who work here, are very dedicated.' = All the teachers are dedicated. 'Who work here' is just extra information about which teachers we are discussing (those who work here). It does not limit or define which teachers are dedicated.
This distinction matters in real communication. The wrong use of commas changes the meaning of the sentence.
THE OMISSION RULE — when the relative pronoun can be dropped:
In DEFINING clauses where the relative pronoun is the OBJECT of the clause, it can be omitted:
WHOM — formal object form of 'who':
In formal written English, 'whom' is used when the relative pronoun is the object:
Is the relative clause essential to identifying which person or thing? → defining (no commas, can use that). Is the noun already clearly identified — and the clause just adds extra info? → non-defining (commas required, no 'that'). Is the noun a person? → who (or that in defining only). Is the noun a thing? → which (or that in defining only). Is the relative pronoun showing possession? → whose. Is the noun a place? → where. Is there an extra pronoun inside the relative clause ('who she appointed')? → remove the extra pronoun.
Choose the correct relative pronoun — or decide whether commas are needed. Think about whether the clause is defining or non-defining, and whether the noun is a person, thing, or place.
Each sentence contains an error. Write the correct version and explain why — then reveal the answer.
Use this sequence directly in class — guided discovery, no textbook needed. Tap each step to mark it done.
STEP 1 — ESSENTIAL OR EXTRA? (8 minutes): Write two sentences on the board:
STEP 2 — WHO, WHICH, THAT, WHOSE, WHERE (8 minutes): Build a reference chart on the board through student input.
Who: The teacher who... / The children who...
Which: The book which... / The school which...
That: The book that... / The students that... (defining only)
Whose: The student whose work... / The school whose results...
Where: The village where... / The classroom where...
Ask students to produce one example for each. Confirm: 'that' is never used in non-defining clauses.
STEP 3 — THE COMMA MEANING (5 minutes): Write this pair:
'Students who practise English regularly improve fastest.' (some students — those who practise)
'Students, who practise English regularly, improve fastest.' (all students — and they all practise)
Ask: do these mean the same thing? No — the first restricts the meaning to a subset of students. The second makes a statement about all students. The comma is a meaning signal, not just punctuation.
STEP 4 — PRODUCTION DRILL (5 minutes): Give students five sentence starters. They must complete each with a relative clause — and decide: is the extra information essential (defining) or additional (non-defining)?
STEP 5 — ERROR HUNT (5 minutes): Write five sentences — some with which/who confusion, some missing commas, some with extra pronouns. Students correct in pairs. Name each error type as it is corrected.
Use directly in class — copy, adapt, or read aloud. No printing needed.
For each strategy, choose the option that best describes where you are now.
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