Czasowniki modalne (Modal Verbs)

Modal Verbs — Complete Guide

Modal verbs are auxiliary verbs that express ability, possibility, permission, obligation, advice, or deduction. They do NOT change form (no -s, no -ing, no -ed). They are followed by a bare infinitive (without "to").

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Grammar Rules for ALL Modals:

• No -s in third person: She can swim. (NOT: She cans)
• No "to" after modal: You must go. (NOT: You must to go)
• No "do/does" in questions: Can you help? (NOT: Do you can help?)
• Negative: modal + not: She cannot/can't come.

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1. CAN / COULD

| Use | Can (present) | Could (past / more polite) |
|-----|--------------|---------------------------|
| Ability | I can swim. | I could swim when I was 5. |
| Permission (informal) | Can I sit here? | Could I use your phone? |
| Possibility | It can be dangerous. | It could rain later. |
| Request | Can you help me? | Could you help me? (more polite) |
| Offer | I can carry that for you. | — |

Could have + V3 = past possibility that didn't happen:

• You could have told me! (but you didn't)
• She could have been a great singer. (but she chose a different path)

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2. MAY / MIGHT

| Use | May | Might (less certain) |
|-----|-----|---------------------|
| Possibility | It may rain tomorrow. (50%) | It might rain. (30%) |
| Permission (formal) | May I come in? | — |

May/Might have + V3 = speculation about the past:

• She may have forgotten. (It's possible she forgot.)
• He might have missed the train. (Perhaps he missed it.)

May vs. Can for permission:

• May I...? = formal, polite
• Can I...? = informal, everyday

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3. MUST / HAVE TO

| Use | Must | Have to |
|-----|------|---------|
| Strong obligation | You must wear a seatbelt. (rule/law) | I have to get up early. (external necessity) |
| Internal vs. external | I must study more. (I feel it) | I have to study — the exam is tomorrow. (situation requires it) |

Must vs. Have to — key difference:

• Must = speaker's authority/personal feeling: You must be quiet in the library.
• Have to = external obligation: I have to wear a uniform at school.
• Must NOT = prohibition: You mustn't smoke here. (It's forbidden!)
• Don't have to = no obligation: You don't have to come. (It's optional.)

Must have + V3 = logical deduction about the past:

• She's not answering. She must have left already. (I'm sure of it.)

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4. SHOULD / OUGHT TO

| Use | Example |
|-----|---------|
| Advice | You should see a doctor. |
| Recommendation | You should read this book. |
| Expectation | The train should arrive at 5. (I expect it to.) |
| Mild obligation | Students should attend all classes. |

Should have + V3 = regret, criticism (past):

• I should have studied more. (I regret not studying.)
• You shouldn't have said that. (It was wrong of you to say it.)

Should vs. Ought to: Nearly identical. "Ought to" is slightly more formal:

• You ought to apologize. = You should apologize.

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5. WOULD

| Use | Example |
|-----|---------|
| Polite request | Would you open the window, please? |
| Hypothetical (2nd conditional) | If I were rich, I would travel. |
| Past habit | When I was young, I would play outside. |
| Willingness (past, refused) | He wouldn't help me. (He refused.) |

Would rather = preference:

• I would rather stay home tonight. (I'd rather stay home.)
• I would rather you didn't tell anyone. (I'd prefer you didn't.)

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6. NEED

As a modal verb (formal, mostly in negatives and questions):

• You needn't worry. = You don't need to worry.
• Need I bring anything?

As a regular verb (more common):

• You don't need to bring anything.
• Do you need to leave now?

Needn't have + V3 vs. Didn't need to:

• I needn't have bought it. (I bought it, but it was unnecessary.)
• I didn't need to buy it. (It wasn't necessary, and maybe I didn't buy it.)

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Modal Verbs for Deduction (Present):

| Modal | Certainty | Example |
|-------|-----------|---------|
| must | ~95% sure (positive) | She must be at home. (I'm almost certain.) |
| can't | ~95% sure (negative) | He can't be 60! (I refuse to believe it.) |
| may/might/could | ~50% possible | She may/might/could be sleeping. |

Modal Verbs for Deduction (Past):

| Modal | Certainty | Example |
|-------|-----------|---------|
| must have | ~95% sure | He must have forgotten. |
| can't have | ~95% sure (neg.) | She can't have failed. |
| may/might/could have | ~50% possible | They may have gone home. |

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Najczestsze bledy (Common Mistakes):

• ✗ She musts go. → ✓ She must go. (no -s)
• ✗ You must to study. → ✓ You must study. (no "to")
• ✗ Do you can swim? → ✓ Can you swim? (no do/does)
• ✗ You mustn't come. (intended: optional) → ✓ You don't have to come. (mustn't = forbidden!)
• ✗ I should studied. → ✓ I should have studied.