https://www.perfect-english-grammar.com/modal-verbs-of-probability.html
1: Talking about the present:
must / might / could / may / can't + infinitive
I am waiting for
Julie with another friend, David.
I ask: 'Where is Julie?'
David
guesses:
-
She must be on
the bus. (I'm fairly sure this is a good guess)
-
She might come
soon. (maybe)
-
She could be
lost. (maybe)
-
She may be in
the wrong room. (maybe)
-
She can't be at home. (I'm fairly sure
this isn't true)
Rephrasing
sentences using Modal Verbs
It’s unlikely
that----- can’t / might (not)
It’s certain that
------ must
Perhaps
-------------- might / might not
It’s impossible
------ can’t
2: Using modal verbs to talk about the past:
must / might / could / may / can't + have + past
participle
You: Where was Julie
last night?
David:
-
She must have forgotten
about our date.
-
She might have worked
late.
-
She could have taken
the wrong bus.
-
She may have felt
ill.
-
She can't have stayed at home.
Debbie was
late last night.
( may / miss the bus)
She
may have missed
the bus.
Emma got
excellent grades at school.
She
must have been a good student.
