Defining Relative Clauses
Review how a defining clause identifies exactly which person or thing the listener means.
ทบทวนการใช้ defining clause เพื่อระบุให้ชัดว่าผู้พูดหมายถึงคนหรือสิ่งใด
TF30 · B1 Grammar · 30 min
Defining or Non-defining Relative Clauses
Decide whether a clause identifies the noun or adds extra information, then make the meaning clear with the right relative word and punctuation.
Why this lesson matters · เหตุผลที่เรียนบทนี้
For learners: You can already add an identifying clue with a defining clause. Now decide whether information is essential or extra so commas and relative words express the intended meaning.
For teachers: Keep the approved TC-GR-01 meaning-first route: removal test, pattern contrast, comma and omission control, listening evidence, profile repair, then an independent briefing with one focused retry.
สำหรับผู้เรียน: คุณเพิ่มข้อมูลเพื่อระบุคนหรือสิ่งของด้วย defining clause ได้แล้ว ขั้นต่อไปคือแยกข้อมูลจำเป็นออกจากข้อมูลเสริม เพื่อให้ comma และ relative word สื่อความหมายที่ตั้งใจได้ชัดเจน
สำหรับครู: คงลำดับ TC-GR-01 แบบเริ่มจากความหมาย: ทดสอบด้วยการตัด clause ออก เปรียบเทียบรูปแบบ ควบคุม comma และการละคำ ฟังหา evidence ซ่อม profile แล้วจบด้วย briefing อิสระและ retry หนึ่งจุด
Your Goal
Distinguish essential identifying information from optional extra detail, use who, which and that with accurate commas, and clarify people or things without changing the intended meaning.
คำอธิบายภาษาไทย
แยกข้อมูลที่จำเป็นต่อการระบุคำนามออกจากข้อมูลเสริม ใช้ who, which, that และเครื่องหมาย comma ให้ตรงกับความหมาย แล้วอธิบายคนหรือสิ่งของได้ชัดเจนโดยไม่ทำให้ผู้ฟังเข้าใจผิด
Why this lesson matters
Commas are not decoration here. “The designer who speaks Japanese” selects one designer from several; “Maya, who speaks Japanese,” adds background information about a person already identified. The listener needs to know whether the clause answers Which one? or simply adds What else?
ภาษาไทย: ถ้าข้อมูลใช้เลือกว่าหมายถึงคนหรือสิ่งใด จะไม่ใช้ comma แต่ถ้าคำนามชัดอยู่แล้วและข้อมูลเป็นเพียงรายละเอียดเสริม จะใช้ comma คั่น ความต่างนี้เปลี่ยนความหมายของประโยคได้
PROGRESS FOCUS What improves today?
MEAN · MeaningDecide whether the listener needs the clause to identify the noun or already knows the noun.
FORM · FormControl who, which, that, commas and safe object-pronoun omission.
USE · Real useBrief a partner clearly and repair descriptions whose information status is ambiguous.
Your 30-minute route
1 · 4 minTest the meaning
2 · 4 minCompare the patterns
3 · 5 minControl commas and omission
4 · 5 minListen for information status
5 · 5 minBuild and repair profiles
6 · 7 minBrief, clarify and retry
Teacher Lesson Plan
Begin with the information problem, not the punctuation rule. Ask: “If we remove this clause, do we still know exactly who or what the noun refers to?”
| Stage | Teacher move | Evidence to collect |
|---|---|---|
| 1 · Meaning | Remove each clause orally and test whether the noun remains identifiable. | Four essential/extra decisions |
| 2 · Notice | Contrast one defining and one non-defining version before naming the punctuation. | Completed contrast map |
| 3 · Control | Require a meaning reason for every comma, relative word and omission. | Five corrected sentences |
| 4 · Listen | Play each profile once for gist and once for evidence; do not reveal punctuation first. | Two listening records |
| 5 · Repair | Let the partner’s interpretation expose ambiguity, then request one focused repair. | Six profiles + two repairs |
| 6 · Perform | Score the first briefing, give one MEAN/FORM/USE target and allow a short retry. | Independent briefing |
Stage 1 · Test whether the noun is already identified
Remove the clause mentally. If the listener can still identify the noun, the information is probably extra.
STUDENT TASK
ESSENTIAL
Which designer?
We hired the designer who speaks Japanese.
Remove the clause → we no longer know which designer.EXTRA
Maya is already clear
Maya, who speaks Japanese, will join us.
Remove the clause → Maya is still identified.- Cover the relative clause in each example.
- Ask: “Do I still know exactly who or what the noun means?”
- Label the clause essential or extra and explain your decision.
Quick meaning testCompare: “The café that opens early is useful.” / “Café 21, which opens early, is useful.” What changes?
Finish evidenceFour essential/extra decisions supported by the removal test.
Teacher Help · Stage 1
Keep the focus on reference: can the listener identify the noun without the clause? Avoid saying that a non-defining clause is simply “unimportant”; it may be useful, but it is not needed to identify the noun.
Stage 2 · Compare defining and non-defining patterns
Meaning controls the relative word, punctuation and possibility of omission.
STUDENT TASK
| Information status | Form | Example |
|---|---|---|
| Defining · essential | noun + who / which / that + clause No commas | Choose the profile that shows the project manager. |
| Non-defining · extra | identified noun, who / which + clause, Use commas; not that | This profile, which shows the project manager, is outdated. |
The decision order
1 Identify the noun → 2 test whether the clause is essential → 3 choose the relative word → 4 add commas only for extra information.
Do not begin by guessing commas. Decide what the listener already knows first.
- Underline the noun in both examples.
- Box the clause and label it Which one? or What else?
- Explain why that is possible in the first pattern but not the second.
Finish evidenceOne completed contrast map and one spoken meaning explanation.
Teacher Help · Stage 2
Use the labels “information needed to identify” and “information added after identification”. Let the learner state the meaning difference before correcting punctuation. Keep advanced style exceptions outside this B1 lesson.
Stage 3 · Control commas and safe omission
Choose the form from the intended meaning, then decide whether the relative word can be omitted.
STUDENT TASK
Complete or correct each sentence. Then give a short meaning reason.
| Sentence | Your decision | Meaning reason |
|---|---|---|
| The consultant ___ handles the Bangkok account called. | who / that · no commas | The clause identifies which consultant. |
| Lena ___ handles the Bangkok account ___ called. | , who …, | Lena is already identified. |
| The dashboard ___ we use every day has changed. | which / that / Ø | Object relative word in a defining clause. |
| This dashboard ___ we launched in May ___ has changed. | , which …, | Extra information; do not omit which. |
| The tablet ___ is beside the blue mug is mine. | which / that | The relative word is the subject, so it cannot be omitted. |
Check the form and reasons
1 who/that, no commas. 2 Lena, who handles the Bangkok account, called. 3 which/that/Ø are possible because the relative word is the object. 4 This dashboard, which we launched in May, has changed. 5 which/that must remain because it is the subject of is.
Finish evidenceFive accurate forms plus a meaning reason for every comma or omission.
Teacher Help · Stage 3
Use a quick subject test: if the clause already has a subject after the relative word, omission may be possible in a defining clause. Do not allow omission in a non-defining clause. Correct one decision at a time: meaning first, punctuation second, omission last.
Stage 4 · Listen for information status
Listen for which noun is intended and whether the clause selects it or adds background detail.
STUDENT TASK
Profile A · Team memberBritish English · Brian Neural
First listen: identify the person. Second listen: decide which clauses are essential or extra.
Profile B · ProductAmerican English · Joanna Neural
First listen: identify the product. Second listen: explain what the commas would show in writing.
- Record the noun and the relative clause for each profile.
- Label each clause essential or extra.
- Choose the relative word and show where commas belong in a written version.
- Compare evidence with a partner before replaying once.
Finish evidenceTwo listening records: noun, clause, information status, relative word and punctuation.
Teacher Help · Stage 4
Play each profile once for gist and once for evidence. The learner must justify the information status from the message, not from an imagined pause alone. Use the two accents for listening variety; they are not imitation targets.
Stage 5 · Build and repair six profiles
Create descriptions whose meaning lets a partner identify the intended noun and recognise optional detail.
STUDENT TASK
Six-profile plan
3 defining: the listener needs the clause to choose the noun.
3 non-defining: the noun is already clear and the clause adds background information.
- Choose six real or realistic people, services, places, products or documents.
- Say each profile without announcing the clause type.
- Your partner identifies the noun and says whether the clause is essential or extra.
- Repair two profiles after the partner asks: “Which one?” or “Is that extra information?”
Ambiguity challengeCompare “Sarah who manages the evening shift will call” with “Sarah, who manages the evening shift, will call.” Decide whether there are several possible Sarahs or whether Sarah is already identified.
Check one document repair
Choose the booking form that has the reference box. The clause identifies which form, so it has no comma. If there is only one known form: The booking form, which has a reference box, is online.
Finish evidenceSix profiles using both clause types and two repairs triggered by listener feedback.
Teacher Help · Stage 5
Do not correct during the first profile. Let the listener’s interpretation reveal whether the information status works. After the six profiles, choose only two high-value repairs and have the learner repeat the complete sentence with the intended meaning.
Stage 6 · Final Practice: brief, clarify and retry
Use both clause types independently in a short real-world briefing.
FINAL PRACTICE
Plan → brief → clarify → repair → retry
- Imagine a new colleague, visitor or classmate needs to understand the people and resources around them.
- Plan four nouns: two that require identifying information and two already-known nouns that receive extra detail.
- Give a 60–75 second briefing using at least two defining and two non-defining clauses.
- Your partner identifies the four nouns and asks one clarification question about information status.
- Repair one weak clause, then retry only the affected part without reading a full script.
Planning example: support agent who handles refunds · booking form that has the reference box · Maya, who leads the project · the new dashboard, which launched in May.
Score the first independent performance
MEAN · MeaningThe listener can tell which clauses identify a noun and which add optional background information.
FORM · FormThe learner controls relative words, commas and safe omission without changing the intended meaning.
USE · Real useThe briefing helps the partner identify all four nouns and the learner repairs one ambiguity after clarification.
0 · Not yetThe listener cannot reliably identify the nouns or distinguish essential from extra information.
1 · With supportThe message becomes clear after a prompt, punctuation cue or model.
2 · IndependentMeaning, form and briefing outcome are clear without teacher-supplied sentences.
Result: 0–2 Rebuild · 3–4 Developing · 5–6 B1 mastery evidence.
Finish evidenceFirst briefing + listener identification + clarification answer + one focused retry.
Teacher Help · Stage 6
Score the first independent attempt across MEAN, FORM and USE. Give one target only: information status, relative word, comma pattern or omission. Preserve the first score and note whether the focused retry improves that target.
Grammar you can use
You can now decide whether a relative clause identifies a person or thing or adds optional background information, then use that distinction to brief, clarify and repair meaning in real communication. Continue through the Dynamic Learning Graph below.
Return to the Learning LibraryContinue your learning path
Report a Lost Item
Use essential identifying information when reporting a lost item so staff can recognise it.
ใช้ข้อมูลจำเป็นเพื่อระบุสิ่งของเมื่อแจ้งของหาย ให้เจ้าหน้าที่รู้ว่าหมายถึงชิ้นใด
Reduced Relative Clauses
Compress relative-clause information into concise B2 descriptions and shortlists.
ย่อข้อมูลจาก relative clause ให้เป็นคำบรรยายและ shortlist ระดับ B2 ที่กระชับ
B1 Grammar Mastery: Explain, Negotiate, and Narrate
Review and combine B1 grammar choices in a longer real-communication mastery task.
ทบทวนและผสานการเลือกไวยากรณ์ระดับ B1 ในภารกิจสื่อสารจริงที่ยาวขึ้น
