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Relative clauses — defining and non-defining
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Identifying and supplementary information
- A defining relative clause helps specify the person, thing or group meant. A non-defining clause presents a separate supplementary comment about an identified referent.
- The distinction concerns the intended message, not whether the added fact is important in real life. Commas signal the supplementary reading in writing.
- Outcome: choose a clause and punctuation that preserve the intended group and information. Start with relative-clause roles. Starting check: does students who registered necessarily mean all students? The clause selects the registered group.
The cat, which ignores instructions, ate the note that explained the rules.
Defining — which person, thing or group?
- The man who called you is my boss identifies the man through the call. A defining clause has no separating commas.
- Compare The volunteers who arrived early opened the room: it selects the early arrivals. It does not say that all volunteers arrived early.
- Removing a defining clause can still leave a grammatical sentence, but change its reference or scope. The deletion test alone cannot decide the intended meaning.
Six lamps are on the desk. Only two flicker. Which instruction selects just those two?
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The defining clause selects the flickering lamps. Separating commas would instead present flickering as a supplementary property of the identified lamps as a group, conflicting with the stated facts.
Non-defining — a supplementary comment
- The volunteers, who arrived early, opened the room presents early arrival as a supplementary fact about the already identified volunteers as a group.
- A clause inside the sentence is set off on both sides: My boss, who is very kind, called me. At the end, one introductory comma is enough: I called my boss, who was very kind.
- A unique name or a family relationship does not mechanically choose punctuation. Use the context and intended information; do not infer someone’s family structure from a comma exercise.
Do the commas matter here?
Read whether the written relative clause selects a referent/subset or adds supplementary information. Punctuation marks that intended relation; deletion alone is not a reliable test.
In standard writing, how is a supplementary (non-defining) relative clause separated from the main clause?
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It is set off with commas: one before a final supplementary clause, or a pair when the clause is inside the sentence. This signals its information status, not that the fact is unimportant.
Translate into one English sentence using a non-defining who-clause to add the description: 我老板人很好,他给我打了电话。
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One solution is “My boss, who is very kind, called me.” The task requests that supplementary construction; it is not the only natural way to translate the Chinese.
Which sentence sets off a final supplementary clause correctly?
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One comma introduces a final supplementary clause; the full stop ends the sentence. A second comma is needed when the clause is internal, not between who and its verb.
More than who and which
- Standard non-defining clauses can use who, whom, whose or which, as appropriate: Nora, whose bike was stolen, took the bus. They do not use relative that, and their relative word is not omitted.
- Supplementary location and time clauses also occur: We returned to the hall, where the meeting had begun. Choose the form for the relation you mean.
- In a defining clause, an object relative may be omitted; a subject relative may not: the book I bought but the book that fell. “Defining” does not mean that every relative word is optional.
Complete this supplementary clause about a thing: “My phone, ___ is new, broke.”
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Non-defining + a thing → which (never “that”): “My phone, which is new, …”.
Does this use a standard non-defining relative frame? “My boss, that is kind, called me.”
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Non-defining clauses can't use “that”: use “who”: “My boss, who is kind, …”.
Compare “the note I copied” and “the note that fell”. Which explanation is sound?
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I is the subject of copied, with the note as object. In that fell, that supplies the subject. Omission depends on role and construction, not the absence of commas alone.
Repair the intended scope
- My mother who lives in Beijing is kind should not be marked wrong solely because the noun is mother. In ordinary contexts a supplementary description is likely: My mother, who lives in Beijing, is kind. Identify the intended reading rather than asserting a universal family rule.
- He failed, which surprised us can use which to refer to the whole preceding fact. He failed, it surprised us needs a sentence boundary or a coordinating construction in standard writing.
- Near miss: if only two of five parcels are damaged, The parcels, which are damaged, need replacing wrongly presents damage as a fact about the whole identified group. The parcels which are damaged need replacing selects the damaged subset.
Match each sentence to its specific relative-clause function. A whole-event comment is also supplementary.
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The first relative identifies the man through the call. The second adds a description of the identified boss. The third comments on the whole fact of his lateness; it too is supplementary, but its specific function differs from a description of a person. The supplied descriptions distinguish these functions rather than treating whole-event and non-defining as mutually exclusive categories.
In standard writing, can relative that replace which in this whole-event comment? “The bus left early, which delayed us.”
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No. This supplementary which-clause comments on the early departure as a whole; relative that does not replace which in this frame. The bus left early, and that delayed us is a different grammatical construction with a coordinator, not a relative that-clause.
Deleting who wear gloves from “The workers who wear gloves use this entrance” leaves a grammatical sentence, so the original clause must be non-defining.
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The remaining sentence is grammatical, but it loses the selection of glove-wearing workers. A deletion test cannot replace a check of reference and intended scope.
- Ask what the relative clause selects or adds, then punctuate that intended message.
- Do not use relative that or omit the relative word in standard non-defining clauses. Whose/whom/where/when are not excluded merely because the clause is supplementary.
- Later recall: invent a group and describe only a selected subset; then write a different sentence adding a fact about the whole group. Explain the change. Continue with contrast linkers to connect those facts without changing their scope.
Write one English sentence adding a supplementary description with who or which. Use a non-defining relative clause and appropriate comma punctuation.
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Example: “Shanghai, which is a huge city, has great food.” A final supplementary clause is also possible: “We visited Shanghai, which has great food.” One introductory comma is sufficient when the clause ends the sentence.
Five bikes are in a rack; only two have broken lights. A mechanic writes, “The bikes which have broken lights need repair.” Which reading fits the defining clause as written?
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Without separating commas, which have broken lights selects the relevant subset. The source says only two have that fault; do not expand the claim to all five. Deleting the clause leaves a grammatical sentence but loses the selection. If you expanded the group, mark the qualifying words and state exactly which bikes they select.
A club has eight members. Three booked the early train; the other five will travel later. Write an English message selecting just the three early travellers for a 7:00 meeting. Then add a separate sentence giving a supplementary fact about the already identified organiser, Mina, using a non-defining relative clause. Invent that extra fact. Compare and revise one scope or punctuation issue.
Compare the intended meaning and the relevant clause/form choices. Revise one supported issue; this local self-review does not award correctness or proficiency.
Worked contrasts: preserve the information
- Subset versus whole group: six cups are on a tray, only two are chipped. “Take away the cups which are chipped” selects those two. “Take away the cups, which are chipped” presents the fault about the identified cups as a group. Deleting the relative may leave a grammatical sentence while losing that selection; punctuation does not count people or prove that an unselected group exists.
- Role before omission: in “the note which I copied”, I is the subject and the note is the object, so the defining object relative can be omitted. In “the note which fell”, the relative supplies the subject and stays. Supplementary “the note, which I copied, …” retains its object relative. Fact versus noun: “The printer stopped, which delayed us” comments on the stopping; “The printer, which was old, stopped” adds a description of the printer.
Fresh decisions: choose the relation
- Work through nineteen new independent decisions beside the earlier bike question. Identify the selected group or already identified referent before choosing punctuation. Defining which for a thing is grammatical in British English, even where a style guide prefers that. Supplementary status does not make an important fact unimportant or independently true.
- Choose by grammatical role: whose + noun can express a relationship with a person or thing. In formal preposition-first style, use to whom for a person. For place/time relations compare where we worked with in which we worked; avoid duplicating that relation with where we worked in. A thing photographed is an object: which we photographed, not where we photographed in that intended frame.
Use the possessive relative word: “Our coordinator, ___ badge is orange, will greet you.”
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Whose introduces badge as belonging to the coordinator. It can appear in a supplementary clause; who and which are not the only available relative words.
Use the relative word for a comment on the whole preceding event: “The screen went blank, ___ interrupted the demonstration.”
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Which can refer to the screen going blank as a whole. That does not introduce this supplementary relative; and that would form a different coordinated construction.
Use the formal object form for a person after to: “Dr Lin, to ___ we sent the draft, replied today.”
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To whom is the requested formal preposition-plus-relative frame. Who we sent the draft to is a different possible order; to who is not the formal form requested here.
There are four named guides. Read “The guides, who have radios, will wait by the gate”. What does the supplementary clause present?
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The commas present having radios as a separate comment about the identified guides as a group. They do not make the information unimportant or prove that it is true outside this stated message.
Read “The students who submitted early may leave first”. What is NOT established by this sentence alone?
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The defining clause specifies who has this permission. It does not supply a count or guarantee that anyone is outside the selected group. Do not turn selection into an existence claim about other students.
Which punctuation makes the description supplementary inside the sentence?
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The internal supplementary clause begins before which and ends after roof, so both boundaries take commas. The clause does not extend through the main predicate leaves at noon.
Which standard supplementary clause preserves the object relative?
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A standard supplementary relative retains which even when it is the object of borrowed. Defining-object omission does not carry over to this comma-separated frame.
Which defining form supplies the subject of failed?
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That is the relative subject of failed. Omitting it leaves two unconnected finite predicates; adding it after which duplicates the relative subject in this intended frame.
Choose the accurate judgment about “The tickets that we printed are in the box”.
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The object relative can be omitted in this defining frame: the tickets we printed. The clause still selects the printed tickets and does not become comma-separated supplementary information.
Which sentence uses a supplementary location frame without duplicating its location marker?
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Where already supplies the location relation here. Which we recorded in and in which we recorded are other possible frames. Recorded the studio would make the studio an object, changing the intended relation.
Choose the object-relative frame for a place that the speaker photographed.
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Photographed takes the hall as its object, so which fits that role. Where would express a location for an activity, not the missing object here; it duplicates the object after which.
Which sentence adds a supplementary time relation?
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When links the beginning to the identified month. In which the course began is another time frame; which alone lacks that relation, and when plus final in duplicates it.
Which judgment fits “The theatre, whose roof was repaired last year, has reopened”?
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Whose can express this relationship with a thing as well as a person. The noun roof follows whose; the clause adds the repair as a fact about the identified theatre, without selecting a different theatre.
A speaker says “The backup failed, which worried the team”. Which interpretation fits the intended whole-event comment?
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The stated reading makes which refer to the backup failing. Contrast a noun description such as the backup, which was old. A preceding noun does not force which to describe only that noun.
A family relationship appears in a noun phrase. What should determine whether its following relative is defining or supplementary?
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Family nouns do not license a blanket punctuation rule or a biographical inference. Work out what the speaker is selecting or adding in the actual context; do not invent family facts.
An identified patient’s note reads “Ms Chen, who has a severe allergy, needs a different medicine”. What do the commas mean?
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Information status differs from practical importance. The sentence is a fictional language example, not medical advice or independent evidence about an actual patient; commas neither minimise nor validate its claim.
Which comparison is accurate?
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The punctuation changes how the information is presented. It does not itself count people or require a non-empty late group. Preserve the intended scope rather than assigning quantities from commas.
In British English, defining which is necessarily wrong in “The file which contains the schedule is missing”.
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Defining which for a thing is grammatical in British English. Some style guides prefer that; a style preference is not proof that all defining which clauses are ungrammatical.
Adding commas around a relative clause after a proper name guarantees that the added fact is accurate.
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Commas mark the supplementary presentation, not factual verification. A name does not validate a claim or provide a universal rule for every possible relative-clause context.
Transfer: send the right group
- Select the torn-label parcels without describing every parcel as damaged. Then distinguish permission for trained helpers from a badge fact about the whole group. Keep the shared noon meeting separate from permission to use the machine.
- Draft your club message before comparing it with the earlier guarded model. Identify who is selected and what is added about Mina. Repair a real scope or comma mismatch; copying a model does not demonstrate independent use.
Eight parcels are on a trolley; three have torn labels. Which instruction selects only those three?
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Without separating commas, the relative selects the torn-label subset. The other choices present the fault across the identified whole group, conflicting with five parcels that do not have that fault.
Three of seven helpers have finished training. All seven have badges and will meet at noon. Which handoff preserves both scopes?
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The first clause selects the three trained helpers. The second adds the badge fact about the identified seven without extending machine permission to them all. The noon meeting applies to all seven; it does not establish that all seven have completed training.
Later review: selection before commas
- Tomorrow, choose the signed folders and complete the possessive relative before rereading. Then draft the walking-route message before opening its model. Check the four walkers, six cyclists, meeting time, leader and map information rather than counting commas alone.
- Next: contrast linkers, relative roles or practical writing. The study allowance is provisional across sessions; these written checks and self-comparisons do not certify proficiency.
Usage checked 21 October 2026: British Council, non-defining relative clauses and Cambridge, defining and non-defining clauses. Original local examples and tasks; level labels are teaching targets, not proficiency findings. Independent specialist, language, answer, accessibility and learner review remains pending.
Later, nine folders are on a shelf and only four are signed. Which wording asks for just those four?
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The defining clause selects the signed folders. Commas would present signing about the identified group; all nine conflicts with the four signed folders.
Later, use a possessive relative: “We thanked Rafi, ___ notes had helped the group.”
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Whose introduces the noun notes and links them to Rafi. It fits a supplementary clause; the comma does not force who or which instead.
Later, draft a two-sentence English message. Four of ten members selected a walking route; six chose cycling. Ask only the walkers to meet at 9:00, using a defining relative clause. Ari is the identified leader and carries the maps in a bag. Add that map information using a supplementary clause, and say Ari will lead the walkers. Draft before opening the model, then revise a real scope or form mismatch.
Compare group selection, supplied facts and clause roles with the model and checklist. Several faithful formulations can work; self-comparison does not establish independent correctness or proficiency.