The document discusses the modal perfect tenses in English, which combine a modal verb like "may", "could", or "must" with the perfect infinitive "have + past participle" to express different meanings about past possibilities, abilities, certainties, expectations, desires, and necessities. Some example sentences are provided to illustrate each modal perfect tense, such as "I might have left my mobile at school" using "might have" to express an uncertain past possibility.

1. Modal perfect
Modal + have+ past
participle

2. May/might/could + have + past participle
When we are not sure what happened in
the past. Possibility in the past.
- I can’t find my mobile:
I might have left it at school.
- She was late for school:
She may not have listened the alarm
clock.

3. Could have + past participle
When we had the ability to do something in
the past but did not do it.
I could have borrowed a bicycle, but I
decided to walk instead.
Yesterday I was bored at home. I could
have joined the party.

4. Can’t / Couldn’t have + past participle
When we are sure that something did not happen.
They can’t have closed the museum yet.
It’s too early.
It was sunny. They couldn’t have predicted
the tornado.

5. Must have + past participle
When we are sure that something was
true.
- My maths homework isn’t in my bag:
I must have left it at home.
- She failed the driving license test:
She must have felt terrible.

6. Should / ought to have + past participle
When expectations were not fulfilled
He should have / ought to have studied
more.
When a piece of advice was not taken.
Regret.
You should have / ought to have been more
careful. Driving fast is dangerous.
I shouldn’t have eaten the cake. I feel sick.

7. Would have + past participle
Desire to do something in the past
which in fact could not be done.
I would have gone to the protest, but I
was really busy.
We would have called you, but we
forgot your number.

8. Needn’t have + past participle
An unnecessary past action.
You needn’t have cooked lunch. I was
going to order a pizza. (we didn’t eat
pizza)
• Different meaning: didn’t need to:
We didn’t need to cook lunch because
she ordered a pizza. (we ate pizza)