This document discusses modal verbs used to make deductions based on known facts. It outlines how modals like might, could, may, must, and can't are used with the infinitive to make present deductions at either 50% or 90% likelihood. Modals like must, can't, might, may and could are used with "have" and the past participle to make past deductions at either 50% or 90% likelihood. Examples are provided to illustrate deductive statements using these modal verbs.

1. Modal Verbs of
DEDUCTION
Carlos Pelejero
Myriam Chiner
Luis Vancells

2. USES
• Past: to speculate about the past /to make
thoughts/ to make guesses about the past based
on known facts
• Present: make deductions about the present /
to make guesses about the present based on
known facts

3. GRAMMAR STRUCTURE
• 1- Modals in present
(modal)
Might
Could + infinitive (without –to-) 50%
May
Must
Can´t + infinitive (without –to-) 90%

4. For example….
• Known facts: we are in BCN’s airport and we see
a man carrying a suitcase, who is dressing with
ski clothes, gloves, boots…
• Deduction:
50%  He may come from Alaska
90%  He must come from a northern-country

5. • Modals in the past:
Must
Can’t + have + p.participle 90%
Might
May + have + p. participle 50%
Could

6. The opposites of must and
must have are can't and
can't have, not mustn't and
mustn't have

7. Now… Make deductions!
•

8. BLIND DATE

9. Relax… Adventure
FIST DATE