Modals vs Adverbs of Probability
Understanding how we express
possibility and certainty
What are Adverbs of Probability?
• Adverbs of probability show how likely
something is to happen.
• They often go before the main verb, or at the
beginning of a sentence.
• Examples: definitely, probably, perhaps,
maybe
Examples – Adverbs of Probability
• Placement in sentence:
• • She will definitely win the race.
• • Maybe he forgot to call.
• • Perhaps they are on the way.
• • I will probably see you later.
What are Modals of Probability?
• Modals of probability are modal verbs used to
express degrees of certainty or possibility.
• They are followed by the base form of a verb
(no -ing or -ed).
• Examples: must, might, could, may, can't
Examples – Modals of Probability
• Placement in sentence:
• • She must be tired. (strong certainty)
• • He might come later. (possibility)
• • It could rain tomorrow. (possibility)
• • That can’t be true. (strong negative
certainty)
Key Differences
• Adverbs of probability are used as modifiers in
a sentence, often before verbs.
• Modals of probability are helping verbs that
modify the main verb.
• Both express possibility, but they are used
differently in sentence structure.
Using 'Could'
• Use 'could' to express possibility in the
present or future, or ability in the past.
• • Structure: Subject + could + base verb
• • Used for: general possibility, polite requests,
past ability
• → It could rain later.
• → She could speak three languages when
she was 10.
• → Could you help me with this?
Using 'Could Have'
• Use 'could have' to talk about something that
was possible in the past, but didn’t happen.
• • Structure: Subject + could have + past
participle
• • Used for: missed possibilities or chances in
the past
• → I could have won the race, but I fell.
• → They could have arrived earlier.
• → You could have told me!