Focus
Modal verbs (can, may, could, might, must, should, will, would) are small words that add precise meaning. They are constantly used in IELTS Part 3 Speaking and Task 2 Writing for hedging, opinion, and analysis.
FOUNDATIONS · Theory
Modal Verbs: Can, May, Could, Might, Must, Should
Theory lesson in Grammar Essentials
Lesson notes
Read through the lesson
Skim first
# Modal Verbs
01
Section
The Nine Core Modals
| Modal | Primary meaning | Example |
|---|---|---|
| can | ability, possibility, permission (informal) | I can swim. This can happen. |
| could | past ability, polite request, weak possibility | I could swim at 5. Could you help? This could happen. |
| may | permission (formal), possibility | May I come in? Rain may fall tomorrow. |
| might | weak possibility | He might be late. |
| must | strong obligation, strong deduction | Students must wear ID. She must be tired. |
| should | advice, expectation | You should rest. It should arrive by noon. |
| would | hypothetical, past habit | I would go if I could. We would meet every Sunday. |
| will | future, promise, prediction | It will rain. I will help you. |
| ought to | advice (slightly stronger than should) | You ought to apologise. |
02
Section
Probability Continuum
Modals let you express exactly how certain you are:
| Certainty | Modal | Example |
|---|---|---|
| 100% sure (positive) | will | The scheme will reduce emissions. |
| 90%+ deduction | must | The scheme must be working — emissions are down. |
| 70% likely | should | The scheme should reduce emissions. |
| 50% possible | may / might / could | The scheme might reduce emissions. |
| 10% possible | might not | The scheme might not be enough. |
| 0% sure (negative) | won't / can't | The scheme can't be solely responsible. |
03
Section
Why Modals Lift Your Score
Compare two Writing Task 2 sentences:
❌ Climate change is caused by humans. (band 6 — too absolute) > ✅ Climate change must largely be caused by humans, though some natural variation may also contribute. (band 7+ — nuanced)
The second shows analytical sophistication. Examiners reward this.
04
Section
Hedging — The Band 7+ Habit
Academic English prefers cautious claims over absolute ones. Use modals to hedge:
| Too absolute | Hedged |
|---|---|
| Tourism destroys culture. | Tourism can undermine traditional culture. |
| Education solves poverty. | Education may help reduce poverty. |
| AI will take all jobs. | AI could replace certain job categories. |
Hedging is not weakness — it is accuracy.
05
Section
Common IELTS Mistakes
Mistake 1: "Must" for advice (sounds bossy) > ❌ The government must invest in education. (reads as command) > ✅ The government should invest in education. (advice) > ✅ The government must act quickly. (if urgency genuine)
Mistake 2: "Should" for strong obligation > ❌ Drivers should stop at a red light. (too weak — it's the law) > ✅ Drivers must stop at a red light.
Mistake 3: Double modals > ❌ I will can help tomorrow. > ✅ I will be able to help tomorrow.
Mistake 4: Forgetting modals don't change form > ❌ She musts leave now. > ✅ She must leave now. (no -s)
Mistake 5: Using "have to" when modal is needed > Have to expresses external obligation. Modals express internal judgement.
06
Section
Past Modals
For past deductions, use modal + have + past participle:
| Form | Meaning |
|---|---|
| must have + V3 | Strong past deduction |
| might/may/could have + V3 | Possible past |
| should have + V3 | Past regret / criticism |
| can't have + V3 | Strong past negative deduction |
These structures are strong band-7+ signals in Speaking when telling a story with reflection.
07
Section
Quick Self-Test
Choose the best modal for each sentence.
- You ___ (should / must) bring your passport to the exam — it's required.
- I'm not sure, but it ___ (might / will) rain later.
- She ___ (must / should) have been tired — she drove for 10 hours straight.
- If more people cycled, cities ___ (would / must) be less polluted.
- The government ___ (could / must) reduce taxes to support low-income families.
Answers:
- must (external requirement) •
- might (uncertain) •
- must have (strong past deduction) •
- would (second conditional) •
- could (one option among several — hedging)