Modals · CEFR B2 · Confident
must have / can't have — English modal verbs
A conclusion about the past drawn from evidence. Must have is near-certain yes; can't have is near-certain no.
The shape
must have / can't have / couldn't have + third form
Work out what happened from the evidence.
In Hindi
सबूत से बीती बात का अंदाज़ा। must have यानी ज़रूर हुआ होगा, can't have यानी हो ही नहीं सकता।
CoCap explains every structure in both languages, because a rule you understand in Hindi is a rule you can use in English.
The mistake to fix first
The sentence Indian-English speakers actually produce, and the reason it is wrong.
| Commonly said | Correct English |
|---|---|
He must not have taken the keys — they are still here. | He can't have taken the keys — they are still here. For "it is impossible", English says "can't have", not "must not have". |
Learn these first
These come first. The rest of this makes more sense once they are automatic.
Easy to confuse with
Close enough to be mixed up with this one. Knowing the difference is most of knowing either.
- could have / would haveB2Talk about what was possible but never happened
- should have — the regretB2Say what you wish you had done
Questions people ask
- What is the must have / can't have used for?
- A conclusion about the past drawn from evidence. Must have is near-certain yes; can't have is near-certain no. In practice: work out what happened from the evidence.
- How do you form the must have / can't have?
- must have / can't have / couldn't have + third form.
- What is the most common mistake with the must have / can't have?
- Saying “He must not have taken the keys — they are still here.” instead of “He can't have taken the keys — they are still here.”. For "it is impossible", English says "can't have", not "must not have".
Where must have / can't have fits
Where this structure sits in the ladder, and what surrounds it.
must have / can't have is a CEFR B2 structure — the confident band — and it belongs to modals. CoCap’s syllabus files every structure this way so you can learn in order instead of jumping between whatever a search happened to return.
Reading it is not the same as saying it.
CoCap turns this page into practice: Hindi sentence in, English sentence out, corrected one thing at a time. Free, no card.
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