Modals of Deduction (Present)

• We use modals of deduction to make guesses about situations in the present based on evidence we can see or hear right now.
• Modal
• Meaning
• Example
• must
• Almost certain (100% sure yes)
• He must be at home; his car is in the driveway in Seattle.
• might / could
• Possible (about 50% sure)
• She might be sleeping because all the lights are off in Boston.
• can't
• Impossible (100% sure no)
• They can't be doctors; they are only ten years old in Chicago.
• Remember
• Use must when you have strong evidence that something is true.
• Use might or could when you think something is possible but you are not sure.
• Use can't when you are almost certain that something is impossible.
• Always follow the modal verb with the base form of the main verb (e.g., be, have, live).
• Examples
• Mark must know the new neighbors in New York.
• That delivery van could belong to the people in Flat 4B in Denver.
• They can't be home yet because their Seattle office closes at six.
• Common mistakes
• She must is at home right now.
• She must be at home right now.
• They can't to be spies.
• They can't be spies.

Complete the sentences

• Look at all those heavy boxes; they (must) ____ have a lot of furniture in Chicago.
• Jessica isn't answering her phone in Boston; she (might) ____ be busy cooking dinner.
• That man is wearing a winter coat in July in Miami; he (can't) ____ be feeling very comfortable.
• The lights are on next door in Seattle, so someone (must) ____ be awake.
• Brian hasn't slept all night in Denver; he (might) ____ be exhausted today.
• They bought a ticket to London yesterday, so they (can't) ____ be in Seattle right now.

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