Unit 25: Modals in the past
Who stole Dan's cake?
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- 1 Go beyond intermediate with our new video course
- 2 Reported speech in 90 seconds!
- 3 If or whether?
- 4 5 ways to use 'would'
- 5 Let and allow
- 6 Passive voice
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- 8 Mixed conditionals
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- 12 The continuous passive
- 13 Future perfect
- 14 Need + verb-ing
- 15 Have something done
- 16 Wish
- 17 Word stress
- 18 Different ways of saying 'if'
- 19 Passive reporting structures
- 20 The subjunctive
- 21 When and if
- 22 Inversion
- 23 Phrasal verbs
- 24 The future
- 25 Modals in the past
- 26 Narrative tenses
- 27 Phrasal verb myths
- 28 Conditionals review
- 29 Used to - review
- 30 Linking words of contrast
Session 1
Dan wants to eat his cake but it's gone missing... He had a good idea about who took it. Learn how to use modal verbs to talk about possibility in the past - all in 90 seconds!
Activity 1
English Class
Rob must have eaten Dan's cake: modals in the past
Dan was looking forward to eating a piece of cake he'd brought into the BBC. But when he looked for it in the fridge, it was gone. He's sure Rob took it because he's done that before.
How do you use modal verbs in the past to express that idea? Dan has a 90-second lesson to explain all.
Watch the video and complete the activity

Hi guys. Dan for BBC Learning English. As you can see, I'm not at all happy about this situation. Something's gone missing. Now, this week, we're gonna talk about modals with a past meaning. And as usual, we're going to do the whole thing in 90 seconds. Excuse me.
So, as you know, English has modal verbs. There are nine of them in total. Examples are: must; can't; may; might and could. Now, these verbs are normally followed by the infinitive. And they're special because they don't change their form for person or to show time. They have a present meaning. But, when we want to use them with a past meaning, we use the modal verb + have + the past participle. In this case, Rob must have eaten my cake.
Now, Rob must have eaten my cake is a measure of confidence. It means that I am extremely confident that Rob did this at some time in the past. When we change the modal verb, we change the level of confidence. For example, Rob can't have eaten my cake. This means I think this is impossible. But I know he did it.
Let's make it less certain. Rob may have eaten my cake. This means it's possible. Maybe he did, maybe he didn't. I'm not sure. And the same for might. Rob might have eaten my cake. Finally, at the lowest level of confidence, meaning this is possible but I'm not %100 sure at all: Rob could have eaten my cake. But that's not true because Rob must have eaten my cake. Rob always eats my cake. I suppose it's my fault.
The last set of modal verbs that we can talk about is should. When we make a mistake in the past. This is called hindsight. So, maybe I shouldn't have left it… (alarm) I should have been a bit quicker… Maybe I shouldn't have left it in the fridge. Maybe I should have put my cake at my desk. But Rob – come on man. Anyway guys. Modal verbs in the past. It's modal + have + the past participle. Don't forget. I've got to go and sort Rob out. See you next time OK? (Roars)
Summary
You can express degrees of certainty about things that happened in the past using modal verbs like must, can't, may, might and could.
Very certain
When you are very certain that something has happened, use must.
Rob must have eaten my cake. (He's done it before and has crumbs on his lips)
Less certain
When you are less certain, use may, might or could.
Rob may have eaten my cake. (It's possible but there isn't strong evidence)
Rob might have eaten my cake.
Rob could have eaten my cake.
Impossible
When it's impossible that something has happened, use can't.
Rob can't have eaten my cake. (He's not at work today)
Mistakes in the past
When you want to talk about something you regret doing in the past, use should.
I shouldn't have left my cake in the fridge. (Rob stole it and I'm unhappy. It was a mistake to leave it in the work fridge)
Form
We use the modal verb + have + past participle
You shouldn't have drunk that much whiskey.
It must have rained last night. The ground is so wet.
I can't have lost my keys. I remember putting them in my bag.
To do
You should have studied... It's time to test your knowledge with this quiz. Good luck!
Where's my car?
5 Questions
I parked it here earlier but now it's gone. Can you use the right modal to tell the story?
Help
Activity
I parked it here earlier but now it's gone. Can you use the right modal to tell the story?
Hint
The car was there and now it isn't. Those are facts.Question 1 of 5
Help
Activity
I parked it here earlier but now it's gone. Can you use the right modal to tell the story?
Hint
How certain is it that my wife moved it?Question 2 of 5
Help
Activity
I parked it here earlier but now it's gone. Can you use the right modal to tell the story?
Hint
How many four-year-olds do you know who can drive?Question 3 of 5
Help
Activity
I parked it here earlier but now it's gone. Can you use the right modal to tell the story?
Hint
Who deals with illegal activity?Question 4 of 5
Help
Activity
I parked it here earlier but now it's gone. Can you use the right modal to tell the story?
Hint
This is talking about mistakes in the past.Question 5 of 5
Excellent! Great job! Bad luck! You scored:
End of Session 1
That's it for this session. Dan's angry... I hope Rob has a good excuse for stealing his cake. He should have thought about that before helping himself.
Next
Join us for News Review as we discuss a major story in the news, and the language you need to understand it.
Session Grammar
Express degrees of certainty about things in the past using modal verbs like must, can't, may, might and could.
Very certain
Use must.
Rob must have eaten my cake. (He's done it before and has crumbs on his lips)Less certain
Use may, might or could.
Rob may/might/could have eaten my cake. (It's possible but there isn't strong evidence.)Impossible
Use can't.
Rob can't have eaten my cake. (He's not at work today.)Mistakes in the past
Use should.
I shouldn't have left my cake in the fridge. (Rob stole it and I'm unhappy. It was a mistake to leave it in the work fridge)Form
modal verb + have + past participle