The document discusses the uses of the words "can", "can't", "must", and "mustn't" as they relate to permission, offers, requests, prohibitions, obligations and requirements. Can is used to ask permission, make offers, or requests. Can't expresses prohibition. Must denotes obligation or requirements. Mustn't prohibits actions.

1. CAN CAN’T
MUST MUSTN’T

2. CAN
•Permission
-Can I go to the bathroom, please?
• Offer
-Can I help you?
•Request
- Can you lend me some money, please

3. CAN’T
•Prohibition
- You can’t speak spanish in the classroom
- They can’t smoke inside the hospital

4. MUST
• Obligation
- He must clean his bedroom.
• Requirement
- You must have a driver’s licence

5. MUSTN’T
• Prohibition
- You must not (mustn’t) flight with knives and
explosives.