Advanced Modals of Deduction
Grammar · PracticePracticeC1
must, can’t and might for reasoning about the present and past.
1Choose the best answer Tap an answer. You see why straight away.
Score: 0 / 10
1. The lights are off and the car is gone. They ___ be out.
2. He answered every question perfectly. He ___ have studied hard.
3. She said she was in Paris, but I saw her here yesterday. She ___ have been in Paris.
4. It’s only 8 a.m. — he ___ be at work already; it doesn’t start until 9.
5. I’m not sure, but she ___ be running late — there’s a lot of traffic today.
6. You’ve been working all day without a break. You ___ be exhausted.
7. He’s a doctor, so he ___ know a lot about medicine.
8. She ___ have forgotten — she always remembers birthdays.
9. I heard a noise. It ___ be the neighbours, or it could be the wind.
10. They left three hours ago, so they ___ have arrived by now.
Answer key — Advanced Modals of Deduction (C1)
- A — must. Strong positive deduction based on evidence: must be.
- A — must. Strong deduction about the past: must have + past participle.
- B — can’t. Strong negative deduction: can’t have + past participle (impossible).
- B — can’t. Logically impossible given the facts: can’t be.
- C — might. Uncertain, possible deduction: might be.
- A — must. Strong positive deduction: must be.
- A — must. A strong logical deduction from a known fact.
- B — can’t. Strong negative deduction: can’t have + past participle.
- C — might. An uncertain possibility: might be.
- A — must. Strong deduction about a likely completed action: must have arrived.
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