Modal verbs short table

Modal verb

Concrete set of meanings

Imperative set of meanings

Suppositional set of meanings

Can/could

• Mental ability (inability), capability resulting from knowledge or skill

• Physical ability (inability) resulting from physical strength

• Possibility (impossibility):
  – factual (circumstantial);
  – theoretical (poss. of idea);
  – possibility due to the existing rules or laws

• Unreality (only could)

• Special questions (only could)

• Asking for permission

• Granting permission

• Prohibition

• Request

• Suggestion (only could)

• Offer

• Reproach (only could)

• In ? sent. doubt, strong doubt, astonishment

• In – sent. improbability or incredulity

May/might

• Factual possibility (circumstantial)

• Hypothetical possibility

• Asking for permission

• Granting permission

• Prohibition

• Reproach (only might)

• Supposition implying doubt and uncertainty

Must/to have to

• Immediate obligation (from the speaker’s point of view), duty, necessity

• Absolute necessity with no freedom of choice

• Obligation depending on a law or a rule

• Asking about the necessity of performing an action

• Absence of necessity (to have to/to have got to)

• Order

• Prohibition

• Strong advice

• Invitation

• Supposition implying strong probability, almost a conviction, strong likelihood

• Logical supposition, deduction

Should/ought to

• Moral obligation or duty

• Asking about one’s duty

• Advice

• Asking for advice

• Criticism, namely, disapproval or reproach

• Probability

• Logical expectation

Emotional should

Auxiliary should

• In rhetorical question Why?

• In negative rhetorical question Why?

• In object clauses introduced by why

• In appositive clauses introduced by why

• In exclusive construction “who should do smth. but smb.”

• In object clauses after expr. of regret, surprise, pleasure, displeasure

• In object clauses following the main clause with it as a formal subject

• With the Indefinite Infinitive in the subject, object, appositive clauses and adverbial clauses of purpose, problematic condition and problematic concession.

• With the Indefinite Infinitive in the main clause of a complex sentence with an adverbial clause of unreal condition.

• With the Perfect Infinitive in the main clause of a complex sentence with an adverbial clause of unreal condition.

• Should is also used as an auxiliary verb to build the form of the Future-in-the Past tense, which is used according to the rules of the sequence of tenses.

To be to

• Planned arranged necessity, obligation arising out of the arrangement

• Something that is destined to happen, smth. unavoidable

• Theoretical possibility

• Order contextually dependent
  – mutual arrangement
  – strict official order

• Instructions

• Asking about the necessity of performing an arranged action

• With strict prohibition

Need

Modal verb

• Asking about the necessity of performing an action for a particular occasion

• Absence of necessity of performing an action for a particular occasion

Notional verb

• Necessity of performing a habitual action

• Asking about the necessity of performing a habitual action

• Non-necessity of performing a habitual action

• Internal obligation caused by the state of the person or thing
  
  

Will/would

• Willingness (unwillingness), strong intention, determination

• A refusal to perform an action

• A lifeless thing that fails to perform its immediate function

• Habitual or recurrent actions

• Natural behavior or quality

• Disapproval of something expected

• A polite request

• Making an offer

• Invitation

• Order

• Supposition implying probability

• Supposition implying the desirability of future action

Shall

• Promise

• Threat or warning

• Asking for instructions

• Making an offer

• Suggestion

• Order or instruction

Dare

Modal verb

• Courage, impudence, impertinence, effrontery to do something

Notional verb

• Courage, impudence, encouragement