اللغة الإنجليزية 10 فصل ثاني

العاشر

Modal Verbs for Speculation in the Past.

We use these when we look at evidence from the past and make a "guess" about what happened.

Unlike speculating about the present, for the past, we use a specific structure:

Modal Verb + have + Past Participle (V3)

Use must have when you are almost 100% sure that something happened because the evidence is very clear.

Meaning: "I'm sure that... happened."
Example from text: "His customers must have been really happy." (I am sure they were happy because the food was great).

Use can't have when you are almost 100% sure that something did not happen or was impossible.

Meaning: "I'm sure that... didn't happen."
Example from text: "Julius Caesar can't have prepared his own food." (I am sure he didn't do it because he was an emperor and had servants).

Use these when it is possible that something happened, but you are not certain. You are just suggesting a possibility.

Meaning: "It's possible that... happened."
Example from text: "Caesar Cardini may have created the first version." (Maybe he did, maybe he didn't).

When you want to say "it is possible that something didn't happen," the "not" comes after the modal verb, not after "have."

This exercise shows how to replace phrases like "I'm sure" with modal verbs:

I'm sure that was delicious.

That must have been delicious.
I'm sure the waiters weren't professionals.

The waiters can't have been professionals.
It's possible it was her first day in the job.

It might/could/may have been her first day in the job.
I'm sure they wanted us to be happy.

They must have wanted us to be happy.