The missing colleague
Recover each clue, the modal conclusion and its certainty level.
TF30 · B2 Grammar · 30 min
Modal Deduction about the Present
Build a measured range of present explanations, rule one out and name the evidence that would resolve the uncertainty.
Why this lesson matters · เหตุผลที่เรียนบทนี้
For learners: Build a calibrated present diagnosis from evidence, reject an impossible explanation and identify the next decisive clue.
For teachers: This B2 step deepens the B1 certainty system into ranked competing explanations, contradiction evidence and a next-evidence decision.
สำหรับผู้เรียน: สร้างข้อวินิจฉัยสถานการณ์ปัจจุบันจากหลักฐานอย่างพอดี ตัดคำอธิบายที่เป็นไปไม่ได้ และระบุหลักฐานถัดไปที่ช่วยตัดสิน
สำหรับครู: ขั้น B2 นี้ต่อยอดระบบระดับความมั่นใจจาก B1 ไปสู่การจัดอันดับหลายคำอธิบาย ใช้หลักฐานหักล้าง และเลือกข้อมูลถัดไปที่ต้องตรวจ
Your Goal
Interpret five current clues, produce a calibrated certainty range, reject one impossible explanation, and identify the next evidence needed.
คำอธิบายภาษาไทย
ตีความหลักฐานปัจจุบัน 5 ชิ้น จัดระดับข้อสรุปจากมั่นใจมากไปจนถึงเป็นไปไม่ได้ ตัดคำอธิบายที่หลักฐานไม่รองรับ และบอกว่าต้องตรวจข้อมูลอะไรต่อเพื่อให้ตัดสินได้แม่นขึ้น
Why this lesson matters
At B2, one clue rarely proves one answer. Useful speakers compare competing explanations, calibrate certainty and ask for the evidence that would change the decision.
ภาษาไทย: ในระดับ B2 หลักฐานเพียงชิ้นเดียวมักยังไม่พอ ผู้เรียนจึงต้องเปรียบเทียบหลายคำอธิบาย เลือกระดับความมั่นใจให้พอดี และขอหลักฐานที่จะช่วยเปลี่ยนหรือยืนยันข้อสรุป
PROGRESS FOCUS What improves today?
MEAN · MeaningSeparate observation from inference and match certainty to the quality of five current clues.
FORM · FormControl must, may/might/could and cannot with be, a base verb or be + verb-ing.
USE · Real useCompare explanations, reject one impossible claim and request the next decisive evidence.
Your 30-minute route
1 · 4 minAudit five clues
2 · 4 minCalibrate certainty
3 · 5 minMatch state or action
4 · 5 minCompare explanations
5 · 5 minListen and verify
6 · 7 minDiagnose and retry
Teacher Lesson Plan
Ask for the evidence before accepting a modal. The learner must explain why the same clue supports one conclusion strongly, leaves another open, and rules another out.
| Stage | Teacher move | Evidence to collect |
|---|---|---|
| 1 · Evidence | Rank five clues by reliability, freshness and relevance. | Five evidence audits |
| 2 · Meaning | Build a strong–possible–impossible range without inventing facts. | Six calibrated decisions |
| 3 · Form | Match identity, state, location and current action to the correct complement. | Eight form repairs |
| 4 · Reasoning | Compare four explanations and reject one using contradiction evidence. | One ranked explanation set |
| 5 · Transfer | Use American and British recordings to recover evidence, certainty and the next check. | Two listening maps |
| 6 · Perform | Score MEAN/FORM/USE, set one target and retry only the weak move. | Diagnosis + next evidence + retry |
Stage 1 · Audit the five clues
Decide what each clue proves, suggests and cannot tell you.
STUDENT TASK
OBSERVEState the clue without interpretation.
WEIGHIs it current, reliable and relevant?
LIMITWhat does it still not prove?
| Current clue | What it supports | What it does not prove |
|---|---|---|
| A coffee is warm beside an empty chair. | Someone used the desk recently. | The owner is still in the building. |
| A coat and open laptop remain at the desk. | The owner probably plans to return. | Where the owner is now. |
| A delivery box is unopened. | The contents have not been checked. | Whether the order is correct. |
| The device shows a meeting as active. | The scheduled meeting may be running. | Who is attending. |
| No one answers the office phone. | No one is answering now. | The office is empty. |
- Say each observation without a modal.
- Rate the clue: strong, partial or weak evidence.
- Name one safe inference and one limit for each clue.
- Choose which two clues can be combined.
Evidence audit: “The coffee is warm, so the desk was used recently. That alone does not prove the person is nearby.”
Finish evidenceFive clue audits and two useful clue combinations.
Teacher Help · Stage 1
Do not let the learner add invisible facts. Use three questions: “What can you verify?”, “How current is it?” and “What remains unknown?”
Stage 2 · Build a calibrated certainty range
Place conclusions where the evidence supports them, not where confidence sounds impressive.
STUDENT TASK
| Evidence position | Modal choice | Reasoning move |
|---|---|---|
| Strongly supported | must | Several current clues point to the same explanation. |
| Open possibility | may / might / could | The explanation fits, but alternatives remain. |
| Ruled out | cannot / can’t | A reliable clue directly contradicts the explanation. |
Meaning before form
Must is a strong present conclusion, not certainty about every detail. May, might and could keep alternatives open. Can’t rejects an explanation; mustn’t normally expresses prohibition.
- Create two must conclusions from combined clues.
- Create three possibilities that remain open.
- Reject one explanation with can’t and cite the contradiction.
- Downgrade one must when a supporting clue becomes unreliable.
Check the calibration
Two compatible current clues can support must. One partial clue usually needs may, might or could. Use can’t only when evidence contradicts the claim.
Finish evidenceSix calibrated conclusions and one justified downgrade.
Teacher Help · Stage 2
Ask the learner to point to the exact clue after each modal. If the evidence only makes an explanation possible, require a downgrade. Do not teach percentages as fixed meanings.
Stage 3 · Match the conclusion to a state or action
Keep the certainty meaning while changing the complement after the modal.
STUDENT TASK
| Meaning needed | Core pattern | Example |
|---|---|---|
| Identity or description | modal + be + noun/adjective | The visitor must be the new supplier. |
| Location | modal + be + place phrase | The manager might be in Meeting Room B. |
| Current action | modal + be + verb-ing | She could be speaking to the driver. |
| Habit or general action | modal + base verb | The device may need a software update. |
- Repair: “He must is nearby.”
- Repair: “They might working upstairs.”
- Repair: “The box can’t contains the replacement.”
- Write two identity/state conclusions, two location conclusions and two current-action conclusions.
- Explain whether each sentence describes now or a general condition.
Check three repairs
He must be nearby. · They might be working upstairs. · The box can’t contain the replacement.
Finish evidenceThree repaired forms and six accurate state/action conclusions.
Teacher Help · Stage 3
Keep meaning constant while changing the complement. Gesture “state/location” for be and “action happening now” for be + verb-ing. Correct only the weakest recurring pattern.
Stage 4 · Compare competing explanations
Rank four explanations for one workplace situation and identify the evidence that separates them.
STUDENT TASK
Situation: A colleague’s coat and laptop are at the desk. A warm coffee is nearby, the calendar shows a client call now, and no one answers at the desk.
| Explanation | Initial position | Evidence test |
|---|---|---|
| The colleague is nearby. | strong or possible? | Which two clues support it? |
| The colleague is speaking to the client elsewhere. | possible | What would confirm the call location? |
| The colleague has gone home for the day. | possible or impossible? | Which personal items weaken this? |
| The colleague is sitting at the desk. | ruled out | Which direct observation contradicts it? |
- Give every explanation a modal conclusion.
- Rank them from most to least supported.
- Reject exactly one and state the contradiction.
- Name one next check that would distinguish the top two explanations.
- Revise the ranking if the calendar information is ten minutes old.
Reasoned rejection: “She can’t be sitting at the desk because the chair is empty. She may be taking the client call in another room.”
Finish evidenceFour ranked explanations, one rejected claim and one decisive next-evidence request.
Teacher Help · Stage 4
Accept more than one ranking when the learner cites evidence consistently. The goal is calibrated reasoning, not guessing the teacher’s preferred story.
Stage 5 · Listen, rank and verify
Recover evidence and certainty across two accents, then decide what should be checked next.
STUDENT TASKAmerican English British English
The delayed delivery
Identify the rejected explanation and the next useful evidence.
- Listen once for the situation and list only direct clues.
- Listen again for modal · conclusion · evidence reason.
- Rank the explanations from strongest to weakest.
- Identify one conclusion that is rejected and quote the contradicting clue in your own words.
- State which new evidence would resolve the remaining uncertainty.
Transfer: Give your Stage 4 ranking to a partner. The partner removes one clue; recalibrate one conclusion immediately.
Finish evidenceTwo listening maps, two ranked explanation sets and two next-evidence decisions.
Teacher Help · Stage 5
Audio never starts automatically. Accent variety tests comprehension, not imitation. Replay only the evidence clause when a learner hears the modal but cannot justify it.
Stage 6 · Final Practice: diagnose and verify
Deliver one independent present-situation diagnosis, then improve one precise weakness.
FINAL PRACTICE
Observe → rank → reject → verify → retry
- Choose a work, travel, home or study situation with exactly five current clues.
- Use notes only: clue · reliability · explanation · modal · reason.
- Present a 90-second diagnosis with one strong conclusion, three open possibilities and one impossible explanation.
- Explain which clue rejects the impossible explanation.
- Name the next evidence needed to distinguish the two strongest remaining explanations.
- Your partner changes one clue; recalibrate one claim.
- After one feedback target, retry only the weakest meaning decision, modal form or verification move.
Planning example: coat + warm coffee + active client call · “She must be nearby, but she might be taking the call in another room. She can’t be sitting at this desk because the chair is empty.”
Score the first independent performance
MEAN · MeaningCertainty levels match the strength, freshness and limits of the five clues.
FORM · FormModal + base verb, be or be + verb-ing accurately expresses the intended identity, state, location or action.
USE · Real useThe learner ranks explanations, rejects one with evidence and requests the next decisive check.
0 · Not yetEvidence and conclusion are mixed, or the modal/form prevents a reliable diagnosis.
1 · With supportThe diagnosis becomes clear after an evidence, certainty, complement or next-check prompt.
2 · IndependentThe evidence range, modal forms, rejection and next check are clear without a prompt.
Result: 0–2 Rebuild · 3–4 Developing · 5–6 B2 mastery evidence.
Finish evidenceFive interpreted clues + calibrated range + one rejected explanation + 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: evidence strength, certainty level, complement form, contradiction or next-evidence request. Keep the original score and record whether the focused retry improves it.
Grammar you can use
You can now build and defend a measured present diagnosis, reject an explanation that contradicts the evidence and request the next clue needed. Use the Dynamic Learning Graph below for the next step.
Return to the Learning LibraryContinue your learning path
Modal Verbs for Present Certainty and Possibility
Learn first: calibrate present certainty from individual clues.
เรียนก่อน: ฝึกเลือกระดับความมั่นใจจากหลักฐานปัจจุบันทีละข้อ
Modal Verbs for Real Situations
Compare this evidence-led deduction with the wider system of modal meanings.
เปรียบเทียบการอนุมานจากหลักฐานกับระบบความหมายของ modal ที่กว้างขึ้น
Risk, Response, and Review
Use changing evidence to revise risk decisions in a real emergency review.
นำหลักฐานที่เปลี่ยนแปลงไปใช้ปรับการตัดสินใจเรื่องความเสี่ยงในสถานการณ์ฉุกเฉิน
Modal Deduction about the Past
Move the same evidence reasoning from present clues to a completed past incident.
นำการให้เหตุผลจากหลักฐานแบบเดียวกันไปวิเคราะห์เหตุการณ์ในอดีต
