Modal auxiliary verbs possibility to necessity

Modal auxiliary verbs are used to express variety of moods including possibility to necessity. But, there are many modal verbs with multiple meanings. Hence, to avoid overlapping, I have decided to bring more clarity of modal auxiliary verbs possibility to necessity.

Can modal verb for ability

Can modal auxiliary verb is especially used to express general but self-ability to do something. For specific ability, “be able to” is used.

Examples of can and be able to modal verbs

  • She can sing a classical song. (general ability)
  • He can prepare delicious food. (general ability)
  • She is able to sing a classical song. (specific ability)
  • He is able to prepare delicious food. (specific ability)

May modal verbs for possibility and permission

May modal auxiliary verb is used to express strong possibility, And, might modal verb is preferred for milder possibility.

Examples of May and might

  • It may rain in the morning. (stronger possibility)
  • It might rain in the morning. (milder possibility)
  • Today, he may be late due to huge traffic.

May modal verb is highly used to express permission. But, to grant permission, can modal is taken.

  • May I use your mobile phone? (ask permission)
  • You can use my mobile phone. (grant permission)

Would and could modal auxiliary verbs for request

Modal auxiliary verb “Would” is used to express more formal and polite request. Whereas, “Could” modal auxiliary verb is preferred for less formal and polite to express request.

Could and would examples

  • It is too difficult to manage. Would you help me to manage this event, please?
  • Would you give me your workbook, please?
  • Could you inform my class teacher about my health?
  • Could you keep quiet for some time?

Should and ought to for advice and recommendation

Should modal auxiliary verb is used for common or general advice.  Whereas, “ought to” expresses moral advice or moral duties.

Should modal verb is more common and formal than ought to.

Useful examples of should and ought to
  • Public transport facilities should be accessible for everyone. (recommendation)
  • Student should not make noise. (duty)
  • You should work there for a year. (advice)
  • Chris ought to obey his parents.

Must and have to modal verbs for necessity or compulsion

“Must” modal verb is taken to express necessity. But, “have to” is used to express compulsions to do something. For clarity, ‘must’ is common in family interaction; whereas, ‘have to’ is more applicable in social relationships.

  • He must not escape from responsibility.
  • She must respect her father-in-law.
  • You have to exercise daily to crack this exam.
  • You have to keep your room clean to avoid fine.

Finally, “Shall” modal auxiliary verb is used for legal obligations and offer something.

Can modal verb is also used to make offers.

  • Shall I make an inquiry for you? (offer)
  • Plastic bags shall be banned by laws. (obligation)

These are the major modal auxiliary verbs used to express moods of possibility to necessity.

Functions of preposition

Coordinating conjunction not only but also