Finding out about grammar


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9.1 What Is a Modal Auxiliary Verb?

Modal Auxiliaries generally express a speaker's attitude or mood. For example, modals can express that a speaker feels something is necessary, advisable, possible or probable.
The Modal Auxiliaries in English are: can, could, may, might, ought to, shall, should, must, will and would. Modals do not take a final -s, even when the subject is he, she or it.

Examples:

  • Incorrect: He cans do it.
  • Correct: He can do it.
  • Incorrect: Mary musts do homework.
  • Correct: Mary must do homework.

    • Modals are followed immediately by the Simple Form of the Verb and never followed by the preposition to.

    Examples:

  • Incorrect: He can does it.
  • Correct: He can do it.
  • Incorrect: I shall to do my homework.
  • Correct:I shall do my homework.

    • The only exceptions are ought and have, which are followed by an infinitive (to + the simple form of a verb); ought to, have to.

    Examples:

  • Incorrect: He ought behave better.
  • Correct: He ought to behave better..
  • Incorrect: Maryhas do homework.
  • Correct:Mary has to do homework.

    • There are some similar expressions to these Modal Auxiliaries, and must be preceded by an infinitive (to + the simple form of a verb) that is used in these similar expression.

    Examples:

  • Be able to = can
  • Be going to = will

    • Other expressions:

  • Have to do = must
  • Used to do = could

    • 9.1.1 May – Might

    You can use this modal to express:

  • Polite request: May I borrow your pen?
  • Formal permission: You May leave the room.
  • Possibility: Where is John?
                        He may be at the library
  • Less than 50% certain: He might be at the library.
  • Post He might have been at the library.

    • 9.1.2 Shall

    You can use this modal to express:

  • Polite question to make a suggestion: ShallI open the window?
  • Future with “I, we” as subject: I Shall arrive at nine.
                                                       (Will is more commonly used).

    • 9.1.3 Should

    You can use this modal to express:

  • Advisability: I should study tonight.
  • Past: I should have studied last night.
  • 90% certain: She should do well on the test. (Future only, not present)
  • Past: She should have done well on the test.

    • 9.1.4 Must

    You can use this modal to express:

  • Strong necessity: I must go to class today.
  • I had to go to class yesterday.
  • Prohibition (negative): You must notopen that door
  • 95% certain: Mary isn't in class. She must be sick.
  • Past: Mary must have been sick yesterday.

    • 9.1.5 Can

    You can use this modal to express:

  • Ability:I can run fast.
  • Past:I could run fast when I was a child, but now I can not.
  • Informal Permission:You can use my car tomorrow.
  • Informal Polite Request: canI borrow your pen?
  • Impossibility (Negative only):That can not be true!
  • Less than 50% certain: Where is John?
                         He could be at home.
  • Past: He could have been at home.

    • 9.1.5 Will

    You can use this modal to express:

  • 100% certain:He will be here at six o'clock. (Future only)
  • Willingness: The phone is ringing. I will get it.

    • 9.1.5 would

  • Polite Request: Would you please pass the salt?
                        Would you mind if I leave early?
  • Preference: I would rather go to the park than stay at home.
  • Past: Iwould rather have gone to the park than stayed with you.
  • Repeated action in the past: When I was a child, I would visit my grandparents every weekend.

    • 9.1.8 Ought To

    You can use this modal to express:

  • Advisability: I ought to study tonight.
  • Past: I ought to have studied last night.
  • 90% certain: She ought todo well on the test. (Future only, not present).
  • Past: She ought to havedone well on the test.

    • 9.1.9 Have to

    You can use this modal to express:

  • Necessity: I have to go to class today.
  • Past: I had to go to class.
  • Lack of Necessity (negative): I don't have togo to class today.
  • Past: I didn't have to go to class yesterday.
  • Obligation: She has to hand in the report today, or she will be fired.

    • 9.1.10 Going to

    You can use this modal to express:

  • 100% certain: He is going to be here at six o'clock. (Future only)
  • Definite Plan: I am going to to paint my bedroom.
  • Past: I was going to paint my room but didn't have time.

    • 9.1.11 Used to

    Repeated action in the past:

  • 100% certain: I used tovisit my grandparents every weekend.

    •         Excercise 1

    Use either should or could to complete the sentences.

            Excercise 2

    Use either would or may to complete the sentences.

            Excercise 3

    Use can, can't, could or couldn't to complete the sentences.

            Excercise 4

    Use either may be or maybe to complete the sentences.