Last year you learnt about
PRESENT MODALS (modal verb + bare infinitive):
Deduction about the present:
Don’t call her now. It’s 8 o’clock. She must be bathing
the baby. (We are pretty sure that is the case)
They can’t be at
home. All the lights are off. (We are pretty sure it is impossible)
They may/might be at
the supermarket. (We think it is possible, but we are not completely sure)
Advice:
You should limit your
online time.
This year we are learning about PAST MODALS,
that is, the same modals to make deductions about the past, which involves
using A MODAL VERB + HAVE + PAST PARTICIPLE:
Deduction about the past:
Rob must have eaten my
cake. (I am pretty sure that is the case)
Rob can’t have eaten your
cake because he hasn’t come to work today. (I am sure that is NOT the case)
Tom may/might have eaten it
(It is possible but we don’t really know for sure).
Criticism or Regret:
You shouldn’t have said that.
Now everybody must be thinking you are blaming them.
I shouldn't have bought those shoes. I have another pair
which is quite similar.
A very important aspect of this structure with modal
verbs is the pronunciation of
the auxiliary
form of HAVE, which is weak, very
similar to the preposition OF /əv/.