past modals
– would have, should have, could haveUse:To talk about the past and speculate or imagine how things are / were.• Should have is often used to express criticism or regret about a past action or inaction.• Could have is used to express past possibility that did not in fact happen.You could have hurt yourself. (but you didn’t)
Form:
modal + perfect infinitive
You shouldn't have left the suitcase there. It could have been stolen.
I would have brought it with me.
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past modals – could have, might have, may have, must have, can’t have
Use:
To make deductions about the past.
can’t / couldn’t have may / might / could have must have
0–5% 50% 95–100%
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Language assistant
Can in its positive form is not used for
deduction. It is possible to use can in
negative and interrogative forms.
She couldn’t / can’t have gone home
– her bag is here. ✔
She can / could have forgotten it. ✘
Use:
To make deductions about the past.
can’t / couldn’t have may / might / could have must have
0–5% 50% 95–100%
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Language assistant
Can in its positive form is not used for
deduction. It is possible to use can in
negative and interrogative forms.
She couldn’t / can’t have gone home
– her bag is here. ✔
She can / could have forgotten it. ✘