Modals: Permission and Obligation

Introduction

• Explains the use of modal verbs for permission and obligation.
• Examples include: can, can't, must, mustn't, have to, and don't have to.

Permission

Using can

• Can is used to ask for and give permission.
  • Examples:
    • "Can I sit here?"
    • "You can use my car."
• When used in questions, it asks if something is possible.

Using could

• Could is more formal and polite than can for asking permission.
  • Examples:
    • "Could I ask you something?"
    • "Could I borrow your pen?"

Using may

• May is the most formal for asking and giving permission.
  • Examples:
    • "May I see your passport, please?"
    • "Customers may request a refund within 30 days."

Prohibition

Using can't

• Can't indicates something is against the rules.
  • Examples:
    • "We can't park here."
    • "You can't take photos in the museum."

Using must not/mustn't

• Must not is used for prohibitions, particularly from authorities.
  • Examples:
    • "Visitors must not park in the staff car park."
    • "You mustn't be late to class."

Obligation

Using have to

• Have to shows obligation from external sources.
  • Examples:
    • "We have to wear a uniform."
    • "When do we have to hand in our homework?"

Using must

• Must indicates strong necessity from the speaker.
  • Examples:
    • "I must phone my dad."
    • "You must hand in your homework."

No Obligation

Using don't have to

• Don't have to indicates something is optional.
  • Examples:
    • "You don't have to wear a tie."
    • "You don't have to come with me."

Comments and Clarifications

• Discussion on differences between can/will (informal) and could/would (formal).
• Clarification on usage of "must" and "have to" from different authorities.
• Explanation of why "can't" and "mustn't" can both be used, with "can't" more common in reported restrictions.

Additional Resources

• Links to online courses and grammar exercises to further practice modals and other grammar topics.