Overview
This lecture explains how to use modal verbs to express permission, obligation, and prohibition in English. It covers the meanings and correct usage of key modal verbs for each category.
Modals of Permission
- "Can," "may," and "could" are used to ask for or give permission.
- "Can I leave early?" asks for permission in an informal way.
- "May I use your phone?" is more formal and polite.
- "Could I open the window?" is polite and less direct.
Modals of Obligation
- "Have to" and "must" express strong obligations or requirements.
- "Have to" is used for rules and laws (external obligation).
- "Must" shows personal obligation (internal feeling or decision).
- "Should" or "ought to" give advice or suggest obligation, not as strong as "must."
- Example: "Students must wear uniforms" (rule); "You should finish your homework" (advice).
Modals of Prohibition
- "Can't" and "must not (mustn't)" express prohibition.
- "Can't" tells someone something is not allowed at all.
- "Must not" is used for strong warnings or rules.
- Example: "You can't smoke here"; "You must not touch the wires."
Examples & Practice
- Asking permission: "Can I borrow your book?"
- Giving advice: "You should see a doctor."
- Expressing obligation: "You have to submit the form."
- Prohibiting action: "You can't park here."
Key Terms & Definitions
- Modal Verb — a verb (like can, must, should) used with another verb to express ability, permission, obligation, or prohibition.
- Permission — allowing someone to do something.
- Obligation — something you are required or expected to do.
- Prohibition — something you are not allowed to do.
Action Items / Next Steps
- Practice writing sentences using modals for permission, obligation, and prohibition.
- Review the differences between "must," "have to," and "should."
- Complete any assigned homework or exercises on modal verbs.