The shortest fable tonight, and one of the most famous. It has given us an expression that people still use every day, in every language that has read Aesop.
Aesop’s Fables · Part 1 · Modal verbs: deduction
The Fox and the Grapes
Must, can’t, might, may and could, and their past forms: the grammar of being sure, being fairly sure and guessing, argued over a bunch of grapes by Sophia, Marcos, Demetria, and precisely footnoted by Philo.
🦊 Play the story too: in the gamebook, you are the Fox.Play the gamebook →
SOPHIA
MARCOS
Is it about food? It sounds like it’s about food.
The fable
After Aesop
One hot afternoon, a hungry Fox came to a vineyard. High above his head, a bunch of purple grapes was hanging from a vine on a tall trellis. They looked ripe and sweet and full of juice.
“Those must be the sweetest grapes in the whole valley,” said the Fox, and he jumped. He missed. He took a run and jumped again. He missed again.
He jumped and jumped until he was tired and dusty and his paws were sore, but the grapes were always just out of reach.
At last he sat down, looked up at the grapes, and turned his nose in the air. “They can’t be ripe after all,” he said. “I’m sure they’re sour. I don’t even want them.” And he walked away with his tail held high.
It is easy to despise what you cannot have.
Must: I’m sure it’s true
MARCOS
Those grapes must be delicious. Look at the colour! They’re almost black.
SOPHIA
That is the Fox’s first thought too. Must here isn’t an order. It’s a deduction: you look at the evidence and you are almost certain. They are purple and heavy, so they must be ripe.
Can’t: I’m sure it’s not true
DEMETRIA
And at the end the Fox says: they can’t be ripe. Which is the opposite. And he has no evidence at all!
SOPHIA
Exactly. The opposite of deductive must is can’t, not mustn’t: They can’t be ripe = I’m sure they aren’t. Mustn’t is only for rules: you mustn’t steal grapes.
Might, may, could: perhaps
PHILO
A more honest fox would have said: they might be sour, they may be sweet, I could be wrong. I don’t know, because I can’t reach them.
SOPHIA
Philo has found the humble modals. Might, may and could all mean perhaps: it’s possible, I’m not sure. May is a little more formal; might a little less certain.
Must have, can’t have, might have: deductions about the past
THE CLERK
Somebody has eaten half the grapes I left on my desk. It must be a mouse.
SOPHIA
Almost, but it happened in the past. For deductions about the past, add have + past participle: It must have been a mouse. It can’t have been Marcos, he was here. It might have been the cat.
MARCOS
It can’t have been me.
DEMETRIA
You have purple fingers, Marcos. It must have been you.
Sour grapes
PHILO
And that is why, when somebody says that something they couldn’t get wasn’t worth having, we call it sour grapes. He says he never wanted the prize anyway? Sour grapes. The Fox’s deduction wasn’t logic. It was pride.
Sophia’s summary
| Form | Use | From the fable |
|---|---|---|
| must + verb | I’m sure it’s true (deduction from evidence) | They must be ripe: look at the colour. |
| can’t / couldn’t + verb | I’m sure it’s not true | They can’t be sour; they’re almost black. |
| might / may / could + verb | perhaps; it’s possible | They might be sour. I could be wrong. |
| must have + past participle | I’m sure it happened | A bird must have eaten some. |
| can’t have / might have + past participle | I’m sure it didn’t happen / perhaps it happened | It can’t have been Marcos. It might have been the cat. |
Practice
Answer all the questions, then press “Check my answers”. You can try again as many times as you like.
A · Choose the best form
Choose the form that fits best.
1. The grapes are almost black. They ___ be ripe.
2. He has only just picked them. They ___ be ripe yet: they’re still green.
3. I’m not sure. They ___ be sweet, or they might be sour.
4. Half the grapes are gone. A bird ___ eaten them.
5. It ___ been the Fox. He couldn’t reach them!
6. You ___ steal grapes from other people’s vineyards.
B · Complete the sentence
Write the missing modal, with have if the sentence is about the past.
7. The Fox is licking his lips. He be very hungry.
8. There are purple footprints on the desk. Marcos eaten the grapes. (sure)
9. I don’t know where the Fox went. He gone home, or he might be hiding. (perhaps)
10. She was in Alexandria all day. She been in the vineyard. (sure it’s not true)
C · Right or wrong?
Is the sentence correct English?
11. “They mustn’t be ripe: they’re still green.”
12. “The Fox might have tried again the next day.”
13. “He must to be tired after all that jumping.”
Now be the Fox yourself. Can you reach the grapes, or will you say they’re sour?Play the gamebook →