Modal Auxiliaries English Grammar

What are Modals?

Modal auxiliaries are helping verbs that are used to indicate modality (likelihood, ability, permission, certainty, and obligation). They give information about the tense and function of the main verb in the sentence. They exist only in relation to the main verbs, without which, they make little sense in the sentence.

What are Modals

Characteristics of Modals

How are Modals Used?

In affirmative sentences, the modal auxiliary is placed between the subject and the main verb.

How are Modals Used
  They must call the authorities.
  The students ought to bring their own materials.

In negative sentences, the modal auxiliary is placed between the subject and the negative adverb. 

modal auxiliary is placed between the subject and the negative adverb
  You should not procrastinate
  It may not rain today.

Rules of Modals

  • They do not agree in number with the subject except for the modals ‘need’ and ‘dare’.
She needs to go.She can go.
They need to go.They can go.
  • With the exception of ‘ought’, ‘need’ and ‘dare’, the modal auxiliaries are followed by infinitive forms of verbs without the preposition ‘to’.
She needs to listen.Do you dare to dream?
I can help.Rishab ought to study.
The modal auxiliary  ‘ought’ + ‘to’ is used for duty, necessity, fitness, and moral obligation. 
The modal auxiliary ‘need’ + ‘to’ is used to show requirements.
The verb ‘dare’ when followed by ‘to’ becomes a modal auxiliary and is used to show a challenge. 
  • They have no non-finite forms (‘-en’, ‘-ed’ or ‘-ing’ forms).
  • All tense forms are not represented by the modal auxiliary.

Types of Modals

There are three types of modal auxiliaries:

  • Single concept modals – having just one meaning
  • Double concept modals – having two meanings
  • Past modals – modals in the past tense
Single Concept ModalsDouble Concept ModalsPast Modals
WillMayWould have
MightMustCould have
ShouldWouldMight have
Ought toShallShould have
Had betterCanMay have
 CouldMust have

Single Concept Modals

WillFutureI will buy a new car.
MightDiminished possibility (more unlikely than likely)It might rain today.
ShouldAdvice, SuggestionRanjit should practise daily.
Ought toObligationYou ought to help in times of need.
Had betterAdvice, warningHe had better leave if he wants to catch the 5 pm bus.

Double Concept Modals

MayPermissionMay I borrow your car?
 Increased possibility (more likely than unlikely)It may rain today.
MustCompulsionYou must complete the work.
 AssumptionMahesh is absent today. He must be sick.
WouldPast habit (used to)Mother would send her children to school.
 Future possibilityThey would visit us some day.
ShallSimilar to ‘will’ Used with first person pronounsI shall call you tonight.
 Polite expressionShall I help you?
  Shall I take leave?
CouldPast abilityTushar could eat 10 rotis at a time.
 Present probability (unsure)It could move if we all pushed hard.
CanPresent abilityGavin can help you with your homework.
 PermissionCan I try one of these?

Past Modals

  • These modals help to refer to actions which took place in the past.
  • The structure of such sentences is as follows:
Modal + Have + Past Participle
  You should have asked for help.  
  They ought to have informed us.  
Must have AssumptionHe must have forgotten about us.
May/might haveGuessing/speculatingRaj may have bought these oranges.
Could havePossibility (likely not to have been fulfilled) Yash could have apprised us of the matter.
Would havePossibilityThe guests would have left.
Should have/ ought to haveHypothetical situation which may have been idealHe ought to have helped you.