MODAL VERBS

RULES

• They don't use an 's' for the third person singular (no cans, shoulds or woulds)
• They make questions by inversion ('she can go' becomes 'can she go?)
• They are followed directly by the infinitive of another verb.

CAN

• Ability/suggestion/request
• Examples:
• I can surf
• You can do it!
• Can I eat the last candy?

COULD

• Ability/request/suggestion
• She could dance ballet from a very early age
• Could they give me a ride home?
• I couldn't do it.

BE ABLE TO

• Ability
• He was able to find the park
• She wasn't able to do the job on time.

MAY

• Possibility/formal request
• It may be easier to open the bag on the other side.
• May I go to the restroom?

MIGHT

• Possibility
• He might pass after studying all night!

MUST/MUSTN'T

• Obligation/ prohibition
• You must pay taxes
• She mustn't disrespect her parents

HAVE TO/ DON'T HAVE TO

• Obligation/lack of obligation
• You have to take care of our planet!
• You don't have to go if you don't want to.

NEED TO / NEEDN'T

• Give advice/ lack of obligation
• You need to eat fruits and vegetables
• He needn't go to the supermarket.

SHOULD/SHOULDN'T

• Opinion/advice
• You should go to the party!
• They shouldn't be fighting.

OUGHT TO

• Opinion/advice
• You ought to sky dive at least once in your life!