Modals of deduction

C1.1. - English

Speculation and Deduction

START

We can use modals of deduction to explain something through how sure we are of something.

must might may could can't should ought

Modal verbs

MIGHTMAY COULD + infinitive

SHOULDOUGHT TO + infinitive

CAN'T+ infinitive

MUST+ infinitive

CERTAINTY(negative) We use it when we are almost sure that something is NOT true because of the evidence we have.

CERTAINTY(positive) We use it when we are almost sure that something is true because of the evidence we have.

POSSIBILITYWe use them when we think something is possible, but we are not sure.

To describe a situation we expect to happen.

Past Modal verbs

MIGHT HAVEMAY HAVE COULD HAVE + past participle

SHOULD HAVEOUGHT TO HAVE + past participle

MUST HAVE + past participle

CAN'T HAVE + past participle

CERTAINTY(negative) We use it when we are almost sure that something is NOT true or DID'T happen in the past.

CERTAINTY(positive) We use it when we are almost sure that something was true or happened in the past.

POSSIBILITYWe use them when we think something is possible in the past.

To describe a situation we expect to have happened in the past.

Adjectives and adverbs for speculation

subject +be likely/unlikely to + infinitive OR It is likely/unlikely that + clause

definitelyprobably (adverbs)

be bound to /be sure to + infinitive

- Before the main verb and after the auxiliary in + sentences. They go before the auxiliary in - sentences. - With the verb TO BE, they go after the verb in + sentences and before the verb in - sentences.

- I think she is likely /unlikely to agree to our proposal. - It is likely/unlikely that she agrees to our proposal.

- She'll definitely pass the exam. - She probably won't pass the exam. - He is probably British. - He probably isn't British.

- He is bound to be here in a minute. - He is sure to be here in a minute.

CRIME SCENE INVESTIGATION

What happened at Mrs Brown's office?

It is 9 a.m. You enter your boss's, Anna Brown's office. You see her blood on the floor. She is dead!

You look around the office, terrified.Suddenly, you notice a cigarette butt on the floor!

What is your conclusion?

You look around the office. You see a smashed mobile on the desk.

What is your conclusion?

You look around some more and you see a torn photograph under the desk.

What is your conclusion?

Suddenly, you see a plane ticket to Bali withtoday's date.

What is your conclusion?

You then see an empty wallet under the window.

What is your conclusion?

There is also an empty bottle of wine in the trash bin.

What is your conclusion?

Do you know who killed Anna Brown?

Do you know who killed Anna Brown?

Anna had had a big fight with her fiance about their upcoming holiday in Bali the evening before. She went to her office where she drank and smoke heavily. She was extremely upset so she destroyed the photograph of her and her fiance that she used to keep on her desk. At some point, she tried to call him but she was too drunk to dial, dropped her phone and it smashed into pieces. She wanted to call a taxi to go back home when she discovered she didn't have any money in her wallet. She decided to look for some spare change in her desk when she slipped, fell and hit her head on the edge of her desk. Unfortunately, the blow to the head killed her instantly.

Well done!

Verónica Gaute