Modal Auxiliary

Modal Auxiliaries 

 

Modal verb/Modal Auxiliaries is a type of verb that is used to indicate modality – that is: likelihood, ability, permission and obligation.  

Modal Auxiliary	Function	Differences	Examples
Can	Ability	·  Generaly  used in present tense ·  Indicate stronger posibility ·  Not as formal as could in request	He can climb a tall tree
	Informal permissions		She can use my bike tonight
	Informal polite request		Can i use your telephone?
	Impossibility (negative sentence) accurate  99 %		He’s  just had lunch. He can’t be hungry
Could	Past ability	·   The past form of can ·   Indicate a weaker possibility ·   More formal than can when used in request	He could swim fast when he was at 10 (past)
	Polite request		Could i use your phone?
	Suggestion		I need help in english? You could talk to your teacher
	Possibility, accurate <50%		Where is Clara? She could be at the kitchen.
	Impossibility (negative sentence) accurate 99%		He just had lunch. He couldn’t be hungry
Be able to	Ability	·  Express ability ·  Possible in all tenses	I’m able to help you.
Must	Strong necessity	·   Expresses obligation imposed by the speaker ·   The speaker thinks it is necessary	You must read that book now
	Prohibition (negative sentence)		They must not open the door
	Centrainty, accurate 95%		Clasra isn;t in her room. She must hang out at the mall (present only)
Have to	Necessity	·  Express external obligations ·  Someone else thinks it is necessary	You have to read that book now
	Lack of necessity (not necessary)		Tomorrow is holiday. We don’t have to go to class.
Shall	Polite permission to suggetion	·  Generaly  used in present tense ·  Used more in formal than should	Shall we begin the class?
	Future action (subject I & We)		I shall call you later
Should	Advisablility	·   The past form of shall ·   More formal than shall	You should study harder tonight
	Centrainty, accurate 90%  (expetation)		Ali should do well on the test (future only)
Ought to	Advisability	·   Sounds more formal than should ·   Used less frequently	You ought to study harder tonight
	Centrainty, accurate 90%  (expetation)		Ali ought to have done well on the test (Past)
Will	Centrainty, accurate 100%	·  used to indicate future ·  used in the formation of conditional clause type 1 ·  less polite than would	She will come at 7 a.m (future only)
	Willingness		The phone is ringing. I’ll get it.
	Polite request		Will you please pass the paper?
Would	Polite request	·  used to indicate the past ·  used in the formation of conditional clause type 2 and 3 ·  more polite  and formal than will	Would you please pass the paper?
	preference		I would rather call you than come over
	Repeated action in the past		When i was child, i would go around to my grandparents every weekend (past)
	Polite for ‘want’		I  would like to take a rest for a short while
	Unfulfilled wish		I would have watched TV, but it was broken
Be going to	Centrainty, accurate100%	·  used to for action with plan/thought	She is going to come at 7 a.m
	Fixed plan		I’m going to paint my fence (future only)