Modals of probability

must have = 95% sure something was possible

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might have = maybe

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could have = maybe

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may have = maybe

can’t have = 95% sure

something was NOT possible

Remember

​Certainly 100% It happened

must have = 95% sure something was possible

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​may have = maybe

might have = maybe

​could have = maybe

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can’t have = 95% sure (Probably not)

something was NOT possible

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​Certainly not 100% It didn't happen.

Remember

We use "been" with:

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​NOUNS

​It must have been a spider.

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​VERBS +ING

​My baby might have been sleeping

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​ADJECTIVES

​She could have been bored

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​PREPOSITIONS

​It can't have been in the kitchen.

Remember

Examples of modals of probability without "been"

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​He must have studied in the afternoon.

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​They can't have slept well last night.

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​She might have bought a new motorcycle.

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​NOTE:

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​Each MODAL + HAVE is followed by a past participle verb.