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Session 2

When you're not sure about something you might need to use a modal, a word like might, may, could, must or can’t. In this session we use them to help us solve a murder mystery, and we see them in a news story about life on Mars.

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6 Minute Grammar

Modals of deduction and speculation

Do you know what to say when you're making a guess about a past or present situation? Join Finn and Catherine as they discuss modals in this episode of 6 Minute Grammar.

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Finn
Hello and welcome to 6 Minute Grammar with me Finn.

Catherine
And me Catherine. In today's programme we're having a look at modal verbs.

Finn
Now modal verbs are used in a lot of different ways but in this programme we’re looking at the modal verbs we use when we're talking about things we think are possible or true – both in the present and in the past.

Catherine
That's right. When we don't know something for sure, we often make guesses. And modal verbs can express how sure or unsure we are about our guesses. We'll give you lots of examples…

Finn
And we’ll check what you've learned in our quiz.

Catherine
But first, we're listening to Fiona, who is a science reporter. And Fiona is talking about some ancient fossils that were found in China and Taiwan.

Finn
While you listen, think about this question: Are the fossils from humans?

INSERT
Fiona
The research teams analysing fossils found in China and Taiwan could be looking at something very important. It seems that the fossils can't be from any known human species. They might be the result of breeding between species or they may belong to an unknown human species. The fossils suggest that before modern humans arrived in Asia, more diverse human groups may have lived there than previously thought.

Finn
So that was Fiona. And we asked you: Are the fossils from humans?

Catherine
And the answer is: Maybe. They might be the result of breeding between species or they may belong to an unknown human species.

Finn
So we don't know the answer for sure.

Catherine
Exactly. Now the modal verbs might and may plus an infinitive show that we're talking about a present possibility, not a certainty. The modal verb could does this too, either with an infinitive or with a continuous form. Here's an example.

INSERT CLIP 1
The research teams analysing fossils found in China and Taiwan could be looking at something very important…

Finn
In fact, we can say could be looking, might be looking or may be looking there.

Catherine
That's right: it's a modal verb plus the continuous form of be plus verb–ing.

Finn
But what about this sentence? Listen.

INSERT CLIP 2
It seems that the fossils can't be from any known human species.

Catherine
Fiona uses the modal can’t there. Now we use can't with an infinitive when we believe strongly that something isn't possible. The researchers believe strongly that the fossils don't belong to any known human species. They can't come from a known human species – it's not possible.

Finn
So they must be from an unknown human species.

Catherine
That's right. Must or can't plus an infinitive both help us to express a strong belief that something is or isn't possible.

Finn
When we're less sure about something, we can say, for example, the fossils might not, mightn’t or may not be from a known human species.

Catherine
That's right, but don’t use the negative couldn't like this. It's different. Couldn't plus an infinitive means that something is completely impossible. Right then. Now let's look at possibilities and certainties in the past. Here's the next clip.

INSERT CLIP 3
The fossils suggest that before modern humans arrived in Asia, more diverse human groups may have lived there than previously thought.

Finn
So we can also use might, may, could, can't and must with have and the past participle of the verb when we think something was possible in the past.

Catherine
Yes, we can say may have lived, might have lived or could have lived to express past possibility.

Finn
And we use can't or must with have and the past participle when we're certain about something in the past. For example, the scientists can't have expected to find anything so important.  

Catherine
Exactly. They must have been very excited.

Finn
I'm sure they were!

IDENT           
6 Minute Grammar from BBC Learning English.

Finn
And we're talking about modal verbs.

Catherine
And it's quiz time! For each of these sentences, choose might, must or can’t to fill the gap: Number one: Finn, you got an A grade in physics? Wow. You _____ have studied really hard.

Finn
And the answer is must. You must have studied really hard. I did Catherine.

Catherine
Very good, Finn! Number two: Nick just called. He is stuck in traffic: he _____ be late.

Finn
And this one is mightHe might be late.

Catherine
Well done! Number three: You _____ have seen a ghost. There's no such thing.

Finn
And the answer is can't. You can’t have seen a ghost. There's no such thing. Is there Catherine?

Catherine
I don't think so, Finn. What about you?

Finn
No.

Catherine
We don’t believe in ghosts. And that's the end of the quiz. I hope you got them all right.  

Finn
And there's more about this at bbclearningenglish.com. Join us again soon for more 6 Minute Grammar.

Both
Bye!

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End of Session 2

That's the end of this session. We hope you enjoyed learning about modals of deduction and speculation. Join us in Session 3 to find out about the mystery of technology which is three million years old!

Session Grammar

  • Modals - meaning and use

    Might, may and could – possible in the present or past

    • There might / may / could be life forms on Mars
    • NASA says it may / might / could have been suitable for life in the past

    Might not (mightn’t) and may not - negative possibility in the present or past

    • Their information might not/may not be correct
    • They mightn't have got correct data

    Couldn’t – completely impossible

    • Other scientists say that there couldn’t be life on Mars
    • The gas couldn't be coming from living organisms

    Must and can't – strong beliefs

    • Oh, it can't be true! (I believe strongly that it isn’t true)
    • There must be another explanation (I believe there's another explanation)
    • They must have made a mistake! (I believe they have made a mistake)