Unit 6: Jurassic mystery: unpacking the past
Modals of deduction and speculation - present and past
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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.
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.
Listen to the audio
Hello and welcome to 6 Minute Grammar with me Finn.
And me Catherine. In today's programme we're having a look at modal verbs.
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.
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…
And we’ll check what you've learned in our quiz.
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.
While you listen, think about this question: Are the fossils from humans?
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.
So that was Fiona. And we asked you: Are the fossils from humans?
And the answer is: Maybe. They might be the result of breeding between species or they may belong to an unknown human species.
So we don't know the answer for sure.
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…
In fact, we can say could be looking, might be looking or may be looking there.
That's right: it's a modal verb plus the continuous form of be plus verb–ing.
But what about this sentence? Listen.
INSERT CLIP 2
It seems that the fossils can't be from any known human species.
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.
So they must be from an unknown human species.
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.
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.
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.
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.
Yes, we can say may have lived, might have lived or could have lived to express past possibility.
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.
Exactly. They must have been very excited.
I'm sure they were!
6 Minute Grammar from BBC Learning English.
And we're talking about modal verbs.
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.
And the answer is must. You must have studied really hard. I did Catherine.
Very good, Finn! Number two: Nick just called. He is stuck in traffic: he _____ be late.
And this one is might. He might be late.
Well done! Number three: You _____ have seen a ghost. There's no such thing.
And the answer is can't. You can’t have seen a ghost. There's no such thing. Is there Catherine?
I don't think so, Finn. What about you?
We don’t believe in ghosts. And that's the end of the quiz. I hope you got them all right.
And there's more about this at bbclearningenglish.com. Join us again soon for more 6 Minute Grammar.
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!
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)