Clues in a shared office
Recover the clue, conclusion, certainty level and reason.
TF30 · B1 Grammar · 30 min
Modal Verbs for Present Certainty and Possibility
Read the evidence, choose a certainty level and revise your conclusion when the clues change.
Why this lesson matters · เหตุผลที่เรียนบทนี้
For learners: Turn present clues into measured conclusions, explain the evidence and revise a claim when the facts change.
For teachers: The route separates observation from conclusion, builds three certainty levels, then adds evidence challenge, accent transfer and an independent six-deduction performance.
สำหรับผู้เรียน: เปลี่ยนหลักฐานปัจจุบันเป็นข้อสรุปที่มีระดับความมั่นใจเหมาะสม อธิบายเหตุผล และปรับข้อสรุปเมื่อข้อเท็จจริงเปลี่ยน
สำหรับครู: เส้นทางแยกสิ่งที่สังเกตได้ออกจากข้อสรุป สร้างสามระดับความมั่นใจ แล้วเพิ่มการท้าทายด้วยหลักฐาน การฟังหลายสำเนียง และการสรุปอย่างอิสระ 6 ข้อ
Your Goal
Evaluate six pieces of present evidence, make six modal deductions at three certainty levels, and justify or revise two conclusions.
คำอธิบายภาษาไทย
พิจารณาหลักฐานปัจจุบัน 6 ข้อ สรุปโดยใช้ modal verbs ครบสามระดับความมั่นใจ 6 ประโยค และอธิบายหรือปรับข้อสรุป 2 ข้อเมื่อมีการท้าทายหรือหลักฐานใหม่
Why this lesson matters
A useful conclusion must match the available evidence. Present deduction helps you separate what is strongly supported, merely possible and impossible.
ภาษาไทย: ข้อสรุปที่มีประโยชน์ต้องมีระดับความมั่นใจตรงกับหลักฐาน การอนุมานปัจจุบันช่วยแยกสิ่งที่มีหลักฐานสนับสนุนมาก สิ่งที่เป็นไปได้ และสิ่งที่เป็นไปไม่ได้
PROGRESS FOCUS What improves today?
MEAN · MeaningSeparate strong conclusion, open possibility and impossible explanation from present evidence.
FORM · FormUse must, may/might/could and cannot + base verb accurately; keep deduction must separate from obligation.
USE · Real useState six conclusions, justify the evidence and revise two claims when the situation changes.
Your 30-minute route
1 · 4 minRead the evidence
2 · 4 minBuild three levels
3 · 5 minChallenge conclusions
4 · 5 minPlan six deductions
5 · 5 minListen and revise
6 · 7 minConclude and retry
Teacher Lesson Plan
Do not ask for a modal first. Ask “What does the clue support, what remains possible, and what does it rule out?” Then choose the form.
| Stage | Teacher move | Evidence to collect |
|---|---|---|
| 1 · Evidence | Separate observation from conclusion in six present situations. | Six clue/conclusion distinctions |
| 2 · Form | Build strong, possible and impossible deductions with accurate base verbs. | Nine form-meaning matches |
| 3 · Challenge | Add or remove evidence and require a justified modal change. | Six decisions + two revisions |
| 4 · Plan | Plan six deductions from a balanced evidence board. | Six claim-evidence pairs |
| 5 · Transfer | Use British and American recordings to recover certainty and evidence. | Two listening maps + first explanation |
| 6 · Perform | Score first attempt, set one MEAN/FORM/USE target and retry it. | Six deductions + two revisions + focused retry |
Stage 1 · Separate clues from conclusions
Describe only what you can observe before deciding what it means.
STUDENT TASK
OBSERVATIONWhat can you directly see, hear or verify?
POSSIBLE MEANINGWhich explanations fit the clue?
LIMITWhat does the clue not prove?
| Present clue | Safe observation | Conclusion to test |
|---|---|---|
| A warm coffee is beside an empty chair. | The drink was probably placed recently. | The person is nearby. |
| The meeting-room light is on, but the door is locked. | The room has power and is inaccessible. | Someone is using it. |
| A delivery app shows the driver one street away. | The latest location is close. | The order is arriving now. |
| The laptop is open and a coat is on the chair. | The owner left personal items. | The owner plans to return. |
| No one answers, and the office sign says closed. | The office is not serving visitors now. | A manager is inside. |
| The screen is dark, but the charging light is on. | The device has power. | The device is broken. |
- Underline the direct evidence in all six cases.
- For each case, list one explanation the clue supports and one it does not prove.
- Rank the six proposed conclusions as strong, possible or impossible from the evidence available.
Evidence first: A warm drink supports a recent action. It does not prove exactly where the person is now.
Finish evidenceSix clue/conclusion distinctions and six initial certainty decisions.
Teacher Help · Stage 1
Stop learners from inventing extra facts. Use “I can observe…” and “This may mean…” as separate turns. A strong deduction needs several compatible clues or one highly reliable clue.
Stage 2 · Build the three-level certainty system
Match the strength of the conclusion to the evidence and keep the modal pattern accurate.
STUDENT TASK
| Certainty level | Core form | Evidence-based example |
|---|---|---|
| Strong conclusion | must + base verb | The owner must be nearby; the coffee is warm and the coat is here. |
| Open possibility | may / might / could + base verb | The driver might be waiting around the corner. |
| Impossible explanation | cannot / can’t + base verb | The office can’t be open to visitors; the sign says closed. |
Meaning and form
Must here expresses a strong conclusion, not an obligation. Use cannot/can’t, not mustn’t, for a conclusion that the evidence rules out. All three patterns take a base verb.
- Create three strong conclusions, three possibilities and three impossible explanations.
- Underline the modal phrase and circle each base verb.
- Attach one evidence phrase to every conclusion.
- Downgrade one must conclusion when the evidence is only partial.
Check three form repairs
It must be recent. · She might be nearby. · The screen can’t be completely without power.
Finish evidenceNine accurate certainty-form matches and one justified downgrade.
Teacher Help · Stage 2
Ask “How do you know?” after every must. If the answer supplies no evidence, change must to may, might or could. Correct mustn’t to can’t when the intended meaning is impossible deduction.
Stage 3 · Challenge and revise a conclusion
Change the certainty level when a new clue strengthens, weakens or contradicts the first explanation.
STUDENT TASK
| First conclusion | New evidence | Required response |
|---|---|---|
| The owner must be nearby. | A message says they left an hour ago. | reject or replace the conclusion |
| The room might be in use. | The booking system confirms a session now. | strengthen the conclusion |
| The order can’t be close. | The driver calls from outside. | reverse the impossible claim |
| The laptop must be broken. | The charging light turns green and the screen wakes. | rule out the first explanation |
| The manager could be inside. | A colleague saw the manager leave. | weaken or reject the possibility |
| The device might be charging. | The battery icon rises from 20% to 30%. | strengthen the conclusion |
- Revise all six conclusions after the new evidence.
- Explain two revisions with “At first…, but now…”
- For one item, ask what evidence would be needed before using must.
- Create one misleading overconfident claim and repair it.
Revision frame: “At first, the room might have been empty, but the live booking confirms someone must be using it now.”
Finish evidenceSix certainty decisions, two explained revisions, one evidence request and one repaired overclaim.
Teacher Help · Stage 3
Require the modal to change only when the evidence changes. Do not reward certainty for confidence of delivery. Evidence strength and speaking confidence are separate.
Stage 4 · Plan six present deductions
Build a balanced evidence board with two strong conclusions, two possibilities and two impossible explanations.
STUDENT TASK
1 · CLUEWrite only what is observable.
2 · LEVELStrong, possible or impossible?
3 · CLAIMModal + base verb + evidence reason.
| Evidence notes | Certainty level | Claim and reason |
|---|---|---|
| warm cup + coat + open laptop | strong conclusion | The owner must be nearby because the items are recent and personal. |
| closed sign + no answer | impossible explanation | The office can’t be serving visitors now. |
| location one street away, update five minutes old | open possibility | The driver might be outside soon. |
- Choose one current scene from work, travel, home or study.
- Record exactly six evidence notes without conclusions.
- Plan two must, two may/might/could and two cannot conclusions.
- Add one reason to every claim and mark two claims for a later evidence change.
Finish evidenceSix evidence notes and six balanced, justified deduction plans.
Teacher Help · Stage 4
Keep the evidence board balanced; six versions of might do not meet the goal. Notes should be observable fragments, not full conclusions. The learner must be able to explain why each level fits.
Stage 5 · Listen, justify and revise
Recover certainty and evidence across two accents, then test your own first conclusions.
STUDENT TASK
British English
American English
A new clue changes the answer
Track which conclusion becomes stronger, weaker or impossible.
- Listen once for the scene. Listen again for clue · modal · conclusion · reason.
- Retell one strong, one possible and one impossible conclusion from the recordings.
- Give your six planned deductions to a partner.
- Your partner challenges two: “What evidence supports that level?”
- Accept, defend or revise both conclusions and name one next clue that would help.
Useful response frame“The evidence strongly suggests…, so it must…” · “That is only one clue, so it might…” · “This new fact rules that out, so it can’t…”
Finish evidenceTwo listening maps, six first deductions, two justified responses and one next-evidence request.
Teacher Help · Stage 5
Audio never starts automatically. Accent variety tests transfer, not imitation. If a learner identifies the modal but cannot name its evidence, replay only the reason clause.
Stage 6 · Final Practice: conclude, revise and retry
Explain six present deductions independently and improve one precise meaning, form or evidence weakness.
FINAL PRACTICE
Observe → conclude → justify → challenge → revise → retry
- Use notes only: clue · certainty level · modal · conclusion · reason.
- Present six deductions in 75–100 seconds: two strong, two possible and two impossible.
- Attach at least one observable reason to every conclusion.
- Your partner challenges two conclusions and supplies one new clue.
- Defend or revise both claims and state one next piece of evidence needed.
- After one feedback target, retry only the weakest certainty decision, modal form or evidence link.
Planning example: warm cup + coat + open laptop · strong · “The owner must be nearby because these are recent personal clues.”
Score the first independent performance
MEAN · MeaningStrong, possible and impossible conclusions match the evidence without overclaiming.
FORM · FormMust, may/might/could and cannot take accurate base-verb patterns; mustn’t is not used for impossible deduction.
USE · Real useSix conclusions include evidence, two challenges are handled and at least one conclusion is revised when needed.
0 · Not yetCertainty level, form or evidence link is unclear, so the listener cannot judge the conclusion.
1 · With supportThe claim becomes clear after an evidence question, certainty label, base-verb cue or revision prompt.
2 · IndependentCertainty, form, evidence and revision are clear and appropriate without a prompt.
Result: 0–2 Rebuild · 3–4 Developing · 5–6 B1 mastery evidence.
Finish evidenceSix deductions + six evidence reasons + two challenged conclusions + one next-evidence request + one focused retry.
Teacher Help · Stage 6
Score the first independent attempt across MEAN, FORM and USE. Give one target only: “match the evidence”, “repair modal + base verb”, “replace mustn’t with can’t”, “add the reason” or “revise after the new clue”. Keep the original score and record whether the retry improves it.
Grammar you can use
You can now turn present clues into measured conclusions, explain the evidence and revise a claim when the facts change. Use the Dynamic Learning Graph below for the next step.
Return to the Learning LibraryContinue your learning path
What Went Wrong with the Order?
Listen for visible and reported clues before you state a certainty level.
ฟังจับหลักฐานที่มองเห็นและรายงานมาก่อน แล้วจึงเลือกระดับความมั่นใจ
Modal Verbs for Real Situations
Compare evidence-based certainty with the wider four-purpose modal system.
เปรียบเทียบการสรุปจากหลักฐานกับระบบ modal สี่จุดประสงค์ที่กว้างขึ้น
A Changing Emergency Situation
Track changing evidence and revise a conclusion in an emergency situation.
ติดตามหลักฐานที่เปลี่ยนแปลงและปรับข้อสรุปในสถานการณ์ฉุกเฉิน
Modal Deduction about the Present
Deepen present deduction by building a calibrated range and naming the next evidence needed.
พัฒนาการอนุมานปัจจุบันด้วยช่วงความมั่นใจที่ละเอียดขึ้นและระบุหลักฐานถัดไปที่ต้องการ
