USING MODALS

Modal Structure	Used for:	Examples
can	expressing ability	-I can type 50 words per minute.
could (past of can)		-Before his accident, he could ski well.
May I ....?	polite requests, requesting permission (puis-je...?)	May I have a menu?
Could I ...?		Could I use your pen?
Can I ...? (less polite)		Can I talk to the prisoner?
Could you ...?	asking a favor (pourriez-vous...?) Would you...? Will you...? are also used with the same meaning.	Could you please put out your cigarette?
Can you ...? (less polite)		Can you help me move this refrigerator?
may	expressing possibility (=maybe)	It may rain tomorrow.
might		We might go to Europe for our honeymoon.
could		They could arrive at any time.
must	expressing strong obligation or necessity (Note: must has no past form; use had to)	You must wear a safety helmet in the factory.
have to (past form--> had to)		I have to go because I have an appointment.
had better	expressing strong advice or suggestions	You had better study your irregular verbs.
should	expressing advice or suggestions	I think you should send her some flowers.
ought to		You ought to give her some roses.
must not	expressing prohibition	He must not work because his back is injured.
don't/doesn't/didn't have to	expressing lack of necessity	He doesn't have to work because he won the lottery.
had better not	warning	You had better not go near that dog.
shouldn't	advising against	You shouldn't smoke.