MODALS OF DEDUCTION AND SPECULATION EXERCISE 1 (ESL)
level: Intermediate (B1/B2)
✓ Useful for Cambridge B2/C1
✓ Useful for IELTS
Modals of speculation are used to express how certain or uncertain we are about a present situation. Each modal reflects a different point on the certainty scale: must for near-certainty, might/could for possibility, and can't for near-impossibility. The grammar review below explains the full scale with examples.
GRAMMAR REVIEW! Modals of deduction and speculation
Modals of speculation are used to express how certain or uncertain we are about a present situation. The modal you choose reflects your degree of confidence — from near-certainty to near-impossibility.
Near-certain (positive): Use when the evidence strongly points to one conclusion.
She’s been working for 12 hours straight. → strong deduction about her state
Near-certain (negative): Use when something is logically impossible or highly unlikely.
He just ate an enormous meal. → strong negative deduction about hunger
Possible but uncertain: Use when something is a genuine possibility but not confirmed.
I’m not sure where she is. She ________ be at the gym.
The key is reading the evidence in the sentence carefully. The strength of the deduction — not the grammar alone — determines which modal fits.
Modals of speculation are used to express how certain or uncertain we are about a present situation. The modal you choose reflects your degree of confidence — from near-certainty to near-impossibility.
Near-certain (positive): Use when the evidence strongly points to one conclusion.
She’s been working for 12 hours straight. → strong deduction about her state
Near-certain (negative): Use when something is logically impossible or highly unlikely.
He just ate an enormous meal. → strong negative deduction about hunger
Possible but uncertain: Use when something is a genuine possibility but not confirmed.
I’m not sure where she is. She ________ be at the gym.
The key is reading the evidence in the sentence carefully. The strength of the deduction — not the grammar alone — determines which modal fits.
Choose the correct modal — must, might, could, or can't — to express the speaker's degree of certainty.
CHECK OUT OUR OTHER MODAL VERB EXERCISES:
Past modals 1 (must/might/could/should + have) (I)
Mixed modals 1 (can, should, must) (I)
Mixed modals 2 (can, should, must) (I)
Mixed modals 3 (can, should, must) (I)
Modals with the infinitive 1 (B)
Modals with the infinitive 2 (B)
Modals (couldn’t / might not) (I)
More grammar exercises
Past modals 1 (must/might/could/should + have) (I)
Mixed modals 1 (can, should, must) (I)
Mixed modals 2 (can, should, must) (I)
Mixed modals 3 (can, should, must) (I)
Modals with the infinitive 1 (B)
Modals with the infinitive 2 (B)
Modals (couldn’t / might not) (I)
More grammar exercises
