4.1. Modal Perfect Infinitives
Modal Perfect Infinitives
In the same way that we use modal verbs to say how certain we are about things in the present we can also use them to speculate about the past.
Have + past participle ('have done', 'have been' have stolen' etc.) is called the perfect infinitive. When we use modal verbs to talk about the present they are followed by an infinitive without 'to'. When we use modal verbs to talk about the past they are followed by a perfect infinitive.
must + perfect infinitive
We use must + perfect infinitive when we feel sure about something in the past.
You must have been delighted when you heard you'd won the lottery.
The thieves must have come in through the window. Look – it's still open.
Oh no! Where's my car? Someone must have stolen it!
might, may or could + perfect infinitive
We use might, may and could with the perfect infinitive to say that we think something was possible but we aren't sure.
The thieves might have escaped by car but we can't be sure.
He should be here by now. He may have been caught in traffic or something.
I can't find my purse. I could have left it in the supermarket but I just don't know.
can't + perfect infinitive
We use can't + perfect infinitive when we feel sure something didn't happen in the past.
I thought I saw John in town this morning but it can't have been him – he's in Greece this week.
I can't have left it in the supermarket – I had it on the bus on the way home.
You can't have read the instructions properly. They're perfectly clear.
Source: http://learnenglish.britishcouncil.org/en/quick-grammar/modals-deduction-past
Note that we can also use modals as a complaint or to emphasise emotions (happiness, boredom, anger, etc.)
They could at least have said they were sorry.
How could you be so cruel!
It's all Helen's fault. I could strangle her!
When I heard the news, I was so happy I could have cried.
Pronunciation of modal perfects
Listen to the pronunciation of the verbs and the sentences.
| He must've gone home early | ||
| Could he have forgotten about the meeting? | ||
| He can't have gone- his car's still here. | ||
| He might've gone for a coffee. | ||
| He can't have done. He doesn't like coffee |
Practise using the modal verbs on the following sites:
Caso práctico
Modal perfect infinitives Practice
For each situation, speculate with your partner about what has happened using modal perfect infinitives.
For example: Your friend John asked you all to come in for a meeting at 5 o'clock but when you arrive, he's not there and nor is anyone else>
He could have forgotten about the meeting
He might have gone for a coffee
He could have cancelled the meeting and forgotten to tell you.
| 1. A child walks into class late without talking to anyone. She gives a note to the teacher. She is missing a tooth. |
| 2. A man is on the phone in the street. He looks very excited. Suddenly he punches the air and shouts. "Yes!" |
| 3. A man walked into work, whistling. He was very tanned. |
|
4. Why was she hiding?
Imagen de Martin Vorel en libreshot.Public domain |
5. Why were they arguing? Imagen de jt en Flickr. Public domain |
Reflexión
Now watch the following video with no sound. You are going to tell what happens in it by using modals of deduction and speculation. If you don't know how to start you can look at the feedback, where a possible beginning has been provided.
Video by Wisin and Yandel on Youtube
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| Image by Leandrosciola in Openclipart. Share |
You have to explain the lyrics of the song to a classmate who really likes this group, but because they don't speak Spanish, they haven't got a clue as to what the song is about other than that they like the rhythm and the beat.
You are going to help.
You have 5 minutes to prepare what you are going to say and 3-4 minutes to explain what is going on in the song to your partner.
You might want to have a look at the Spanish lyrics by clicking here.