Alguien me explixa el tema modals of deduction?

Modal Verbs In English : DeductionToday’s lesson will focus on using modal verbs forcertainty, probability, anddeduction.

“Deduction” meansusing the information available to make a guess or draw a conclusion about the facts.

Depending on the information available, you might be more certain that your conclusion is true, or less certain that your conclusion is true – and we use different modal verbs to indicate the degree of certainty.

How certain are you?

Use these modal verbs : 100% – Completely or almost certainmust, can’t, couldn’t80% – Expecting to be certainshould50% – Maybe certainmight, may, couldLet’s look at some examples.

Modal Verbs For CertaintyCERTAINTY ABOUT THE PRESENTWhen making deductions about the present, we usemustif we are sure something is true andcan’tif we are sure that something is impossible.

“He must be a chef.

”For example, if you see this guy, you can say : Hemustbe a chef.

(we are verycertain, because of his uniform and what he is doing)Hecan’tbe a policeman.

(we are very certain he is NOT a policeman)Carla works every day from 9 AM to 5 PM.

Right now it’s 10 : 30 AM, so…Shemustbe at work.

Shecan’tbe at home.

PUT IT INTO PRACTICE!

You’ll see five pictures accompanied by sentences.

For each one, fill in the blank withmust(if you think it is true) orcan’t(if you think it’s not possible).

He _____________ be a vegetarian.

They ______________ be in love.

You studied all night.

You ___________ be exhausted.

That __________ be right…She ____________ love her cat.

CERTAINTY ABOUT THE PASTWhen we consider some present evidence and drawa reasonably certain conclusion about what happened in the past, we usemust haveandcouldn’t haveplus the past participle of the verb.

Must have + past participle

when we draw the conclusion that something DID happenSheila got a tan.

Shemust have spenta lot oftime in the sunlately.

There was one banana left, but now it’s gone.

My husbandmust have eatenmust not have + past participle

when we draw the conclusion that something did NOT happenThe car is still dirty.

Paulmust not have washedit yet.

He barely touched his lunch.

Hemust not have beencouldn’t have + past participle

when we are certain that something was IMPOSSIBLEMarthacouldn’t havetakenyour notebook ; she wasn’t even in class yesterday.

The cookies are gone.

But Ericcouldn’t have reachedthe cookies on the top shelf ; hemust have askedhis older brother to get them.