Understand that clues are not enough: check the context
Write a polite warning message
Today's language goal
To say what a picture must, might or cannot be, and warn someone politely, we need the words of visual clues (distorted, inconsistent, reflection, glitch, gown) and the modals of deduction (must be, might be, can’t be).
Documents
The viral post
May 2024, Met Gala night in New York. Two pictures show the singer Katy Perry in a gown covered in flowers. One post on X gets over 300,000 likes. She was not there: she wrote on Instagram that she had to work. Her own mother believed the pictures. October 2024: other pictures show Disney World's Cinderella Castle under water after Hurricane Milton. They are AI images too; Disney said the resort had weathered the storm.
"Couldn't make it to the MET, had to work" Katy Perry on Instagram, quoted by NPR
"lol mom the AI got you too, BEWARE!" Katy Perry to her mother, quoted by PolitiFact
"There are tell-tale and obvious structural defects in all images including inconsistent reflections in the water" Hany Farid, quoted by AFP
Grammar lesson: modals of deduction: must, might, can’t
To say what a picture must, might or cannot be, and warn someone politely, we need modals of deduction: must, might, can’tFor the teacher: how to run it (8 to 10 minutes)
Show the clue list: wrong carpet, strange hands. Ask: is the picture real? Students answer “it's fake”. Ask: are you 100% sure? Introduce must, might, can't.
Draw a certainty line: can't be (0%) / might be (50%) / must be (100%). Students copy.
Give the past forms with have + past participle for things that happened.
Quick check, then exercises, then the clue grid and the polite comment.
On the board, to copy
Rule
To say how sure we are, use a modal + base verb. must: I am almost sure it is true. might / may / could: it is possible. can’t: I am almost sure it is false.
Form
present: modal + be / base verb: It must be an AI image.
past: modal + have + past participle: She can’t have been there: she was working.
the opposite of must is can’t, not mustn’t.
Use
To comment on clues: The hands are strange, so it might be AI.
To give a verdict carefully, as fact-checkers do.
Clues alone are not proof: use might, not must, until you have checked the context.
Examples from the lesson
The carpet is the wrong colour: the picture must be fake.
Katy Perry can’t have been at the Met Gala: she wrote that she had to work.
These reflections are inconsistent; the image might be AI-generated.
Her mother must have believed it was real.
Common mistakes
Not It must to be fake., but It must be fake.
Not It mustn't be real., but It can't be real.
Not She can't be there last night., but She can't have been there last night.
Not It might is AI., but It might be AI.
Quick check (2 minutes, hands up or mini whiteboards)Must, might or can’t?
The castle is under water but Disney says it weathered the storm: the picture ______ be real.
The hands look strange; it ______ be AI, let's check.
Five sources show the same scene: it ______ be real.
She ______ have been there: she was at work.
Show the answers
1. can't. 2. might. 3. must. 4. can't.
Exercises
EntryRecognition. Say how sure the speaker is: 100% yes, 50%, or 100% no.
CoreTransformation. Rewrite with must, might or can't (present or past).
I'm sure the picture is fake.
Perhaps the post is a joke.
I'm sure she wasn't at the gala.
It's possible the photographer edited it.
I'm sure her mother believed it.
I'm sure the castle didn't flood.
Maybe the account is satirical.
Show the answers
1. The picture must be fake. 2. The post might be a joke. 3. She can't have been at the gala. 4. The photographer might have edited it. 5. Her mother must have believed it. 6. The castle can't have flooded. 7. The account might be satirical.
StretchProduction. Look at the clue grid. Write five deductions, two with must, two with might, one with can't, each with a reason.
Show the answers
For example: The faces of the photographers are distorted, so the picture must be AI. The reflections are wrong; it must be generated. The colour might be edited. The gown might exist, but nobody took a photo of it. Katy Perry can't have been there, because she said she was working.
Going further (for students heading to language studies)Advanced. Rewrite with the structure given and explain the difference.
It is likely that the image was generated. (be likely to)
I'm sure nobody photographed the scene. (There can't ...)
Perhaps she wore a similar gown at another event. (She may well ...)
Show the answers
1. The image is likely to have been generated. 2. There can't have been any photographer at the scene. 3. She may well have worn a similar gown at another event. Be likely to and may well are more formal and nuanced; they are common in journalism and in essays.
CoreComplete with: gown, carpet, spires, weathered. Katy Perry wore a flowery ______ in the fake picture, but the ______ was the wrong colour. Disney's castle had misplaced ______. The resort had ______ the storm.
Show the answers
gown, carpet, spires, weathered.
StretchExplain “tell-tale defects” and give two from the documents.
Show the answers
Defects that reveal the truth. Inconsistent reflections in the water; misplaced castle spires; distorted faces of photographers; strange hands.
Activities
List the clues found by fact-checkers: wrong carpet, distorted faces of photographers, strange hands, inconsistent reflections, misplaced castle spires.
Read Sam Gregory in NPR: instead of hunting for glitches, ask why there are no other pictures of the same scene.
Build a two-column grid: what I see / what I check.
Write a polite comment to someone who shared the picture: inform, do not mock.
Exercise
True or false? Justify. 1. A picture with no visible defect must be real. 2. Online detectors always get it correct. 3. Looking for other pictures of the same event is a good method.
Answer key1. False: tools improve and remove defects. 2. False: NPR reports one detector rated one of the pictures likely human. 3. True: no reliable pictures elsewhere is a strong signal.
Figures of speech in the documents
Personification: the AI got you
“lol mom the AI got you too, BEWARE!” Katy Perry to her mother, quoted by PolitiFact
Katy Perry speaks of AI as if it were a person who tricked her mother: the AI got you. This is a personification. It is funny, but it hides something: AI does not trick anyone on its own; people create and share the pictures.
EntryWho or what “got” Katy Perry's mother?
Show the answers
The AI (the fake picture).
CoreWhy is this personification a little misleading?
Show the answers
Because a person made and shared the picture; AI is a tool, it does not decide to deceive.
StretchRewrite her message without personification, in a polite, informative way.
Show the answers
For example: Mum, careful: this picture was made with AI. I wasn't at the Met, I was working.
Gap-fill worksheet
Word bank : clues, context, detector, reflections, check
Strange hands or blurred faces are ______.
In the Disney pictures, the ______ in the water were inconsistent.
An online ______ can be wrong.
The best habit is to ______ whether other sources show the same thing.
We also judge a picture by its ______: date, place, event.
Answer key
clues
reflections
detector
check
context
Expression task
Now say it
Write a polite comment to someone who shared the Katy Perry picture: inform, do not mock.
EntryThree sentences: hello, the picture is fake, one clue.
CoreFive to six lines with two modals of deduction and one source.
StretchAdd the advice of Sam Gregory: ask why there are no other pictures of the scene.
Tools to use:
distorted, inconsistent, reflection
must, might, can't (have)
according to PolitiFact
Show a model answer
Hi! I loved the gown too, but I think this picture might be AI-generated. The carpet is the wrong colour and the faces behind her are distorted. Katy Perry can't have been at the gala: she wrote on Instagram that she had to work. According to PolitiFact, the images are fake. If there are no other pictures of a scene, it is worth checking.
Levels
Level
Adjustment
Première (B1)
Three clues to tick.
Terminale (B1 to B2)
Add modal verbs of deduction: it must be, it can't be.
C1/C2 extension
Debate: should AI pictures carry a compulsory label?
Bac pro
Record the message orally.
Homework
Write a five-line message to a relative who believed an AI picture. Explain kindly how you checked.
Answer keyModel answer: greeting, a fact (the singer said she was not there), a method (look for other pictures, read a fact-check), a tip, a closing. Respectful tone.