Modal Verbs for Rules & Permission

Permission & "Can" 

Modal Verb: Could 

Using "May" for Permission

Prohibition 

Using "Can't" for Rules and Prohibitions

"must not" / "mustn't" – Formal Rules & Personal Prohibitions

The Contraction: "mustn't"

Obligation 

Using "Have to" for External Obligation

The Modal Verb "Must"

Important Note on Past Obligation

No Obligation 

Modals: permission and obligation Quiz