Lesson
Grammar: must have, might have, can't have, and hedging
Speculate about the past with precision in speaking, and make cautious academic claims in writing. Two skills that separate Band 6 from Band 8.
Speculating about the past
| Certainty | Structure | Example |
|---|---|---|
| Almost certain it happened | must have + past participle | The roads are wet. It must have rained. |
| Possible | might / may / could have + pp | She's late. She might have missed the bus. |
| Almost certain it didn't | can't / couldn't have + pp | He can't have seen us, or he'd have waved. |
| A past mistake | should have + pp | I should have started revising earlier. |
Hedging in academic writing
Strong claims that aren't always true weaken your argument. Hedge them:
- Verbs: appear to, seem to, tend to, suggest
- Modals: may, might, could
- Adverbs: possibly, arguably, largely, generally
- Phrases: It is likely that… / There is some evidence that…
→ Heavy social media use appears to be associated with higher rates of depression, at least among teenagers.
Questions 1–5
Choose the best option.
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The lights are off and nobody's answering. They ___ out.
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She ___ the email. I sent it to the wrong address.
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I'm not sure where my keys are. I ___ them in the taxi.
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I failed the test. I ___ more practice tests.
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Which sentence is best for an academic essay?
Questions 6–9
Complete with the correct form of the verb in brackets.
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The flight was cancelled, so he (must / arrive) late.
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You (should / tell) me you were coming. I would have cooked.
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This (can't / be) easy for her, starting a new job in a new country.
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Rising temperatures (appear) to be affecting crop yields.
