Past modals for deduction

1. Using modal verbs to talk about the past
can’t have

2. Jim is wondering if his
friend Sally has gone
on holiday.
What do you think?
Look at the picture and
try to decide

3. “I wonder if Sally has gone on
holiday.
She can’t have gone on holiday
– her car is still parked outside
her house!”
Jim looks at the evidence (Sally’s car) and makes a deduction.
Can Sally have gone on holiday?
No that’s impossible because her car is still there.

4. can’t have + past participle
We use this to say that something in the past is impossible or unlikely.
We make a deduction by using evidence.
Look at these examples:
Peter can’t have eaten my almond cake. He’s allergic to nuts!
Sophie didn’t buy me a present. She can’t have remembered it’s my birthday!
Can you think of any more examples?