Speculation, deduction and expectation

1. SPECULATIONS, DEDUCTIONS &
EXPECTATIONS
B2, EOI CARTAGENA
Isabel Bastida
SPECULATIONS, DEDUCTIONS
& EXPECTATIONS
C1, EOI CARTAGENA
Isabel Bastida & Ana Mena

2. Choose the right form. Why the other
option is wrong?
1. A: That sounds like the neighbours’ dog.
B: It can’t be / mustn’t be. They’ve gone away for the weekened
and they’ve taken the dog with them.
2. There’s no sound coming from his room. He probably hasn’t /hasn’t
probably woken up yet.
3. A: Didn’t you hear that bang in the middle of the night? It woke me up.
B: Yes, I did. It must be / must have been the wind.
4. Can you turn the music down? If we make too much noise, the woman
upstairs will likely call / is likely to call the police.
5. A: Can I speak to Raymond, please?
B: Sorry, he’s not back yet. He must work / must be working late.

3. PRESENT DEDUCTION, SPECULATION &
EXPECTATION
POSITIVE CERTAINTY
MUST + inf
They must be in Bahamas now. I’ve just seen them scuba
diving on Instagram.
NEGATIVE CERTAINTY
CAN’T/ COULDN’T + inf
They can’t land in Bahamas. Flights are cancelled till
Wednesday due to a hurricane.
PROBABLE CERTAINTY
MAY/ MIGHT/ COULD + inf
MIGHTN’T/ MAY NOT + inf
They may not fly to Bahamas, as she is due in a month.
EXPECTATION
SHOULD/ OUGHT TO + inf
The couple should be home by Friday as their honeymoon lasts
one week. (They are expected to be back by Friday)

4. PAST DEDUCTION & SPECULATION
POSITIVE CERTAINTY
MUST HAVE + pp
The five-year-old boy must have taken his hamster
with him. Someone saw a rodent on the shelves.
NEGATIVE CERTAINTY
CAN’T/ COULDN’T HAVE + pp
The infant can’t have taken all the cereal boxes off
the shelves. His parents kept an eye on him at all
times.
PROBABLE CERTAINTY
MAY/ MIGHT/ COULD HAVE + pp
MIGHTN’T/ MAY NOT HAVE + pp
The boy might have panicked when he found a rat in
the cereal aisle.
REGRET / EXPECTANCY
SHOULD/ OUGHT TO HAVE + pp
I should have called you before you left. (regret)
His parents should have cleaned up the mess.
(Expectation: He expected his parents to have
cleaned up the mess)

5. OTHER EXPRESSIONS FOR
SPECULATION
• Be bound to + inf (inevitable)
He was found guilty of doping and is bound to lose his medal.
• Be likely/ unlikely to + inf (probable)
A new election is likely to be held early next month.
• Will definitely/ probably + verb
Justin will definitely turn down the offer.
• Definitely/probably won’t + verb
Claire probably won’t accept the job.

6. WHAT COULD HAVE HAPPENED?

7. WHAT
COULD
HAVE
HAPPENED?

8. WHAT
COULD
HAVE
HAPPENED?

9. WHAT
COULD
HAVE
HAPPENED?

10. WHAT
COULD
HAVE
HAPPENED?

11. WHAT
COULD
HAVE
HAPPENED?