Verb Types: Modal Verbs-Negative*

Verb Types: Modal Verbs-Negative

April 4, 2019

Native English Instructor

Written by Douglas Shaw

The negative forms reverse the meaning of the modal (to express inability, impermissible or impossibility).

needn’thave todon’t have to 

To form the negative – use the modal add “not” onto the end e.g. “should” becomes “shouldn’t”.

Model verbs – Negative form


 Positive – Can

e.g. – Possibility

  • It can happen, anything is possible.

e.g. – Permission

  • Can I sit here? Yes, you can.

e.g. – Ability

  • I can drive a semi – truck.

 Negative – Can’t

e.g. – Possibility

  • It can’t happen, it’s impossible.

e.g. – Permission

  • No, you can’t sit here. The seat is taken.

e.g. – Ability

  • I can’t fly an airplane.

musthave tohas to

Positive – Must , Have to, Has to

e.g. – Obligation

  • Jeff you have to be at the church by 10:00.

e.g. – Personal opinion – Certainty

  • He must be there on time.
don’t have toneedn’tcan’t

Negative – Don’t have to, Needn’t, Can’t

e.g. – don’t have to, needn’t

  • Jeff, you don’t have to be there to early.
  • Jeff, you needn’t be there early.


Positive – Might, May

e.g. – Personal opinion – Certainty

  • Jeff might be late today.
  • Jeff may be late today.

Negative – May not, Might not

e.g. May not

  • Jeff may not get here on time, he is taking care of his mother.

e.g. – Might not

  • Jeff might not get here on time, he is taking care of his mother.

Positive – Should

e.g. – Weak obligation or advise

  • You should stop smoking because it’s unhealthy.

Negative – Shouldn’t

e.g. – Shouldn’t

  • You shouldn’t smoke so much, it’s unhealthy.
  • You shouldn’t drive while texting because it’s very dangerous.

Obligation – Had to / Must have

The modal verb “must” has two forms “had to” and “must have”. It depends on whether you want to express obligation or if you want to say how certain you are about the probability of something happening.

Present – Must / Have to

e.g. – Must (for both – express obligation)

  • Jeff must go to the chapel.

e.g. – Has to

  • Jeff has to go to the chapel.

Past – Had to

e.g. – Had to (the past of “must” and “have to” is always “had to”).

  • Jeff had to go to the hospital, with his mother.

Personal opinion about probability (Deduction)

Present – Must

When expressing a personal opinion about probability (deduction), we use “must” to express that we feel something is true.


  • He must be here, I see his car.

Past – Must

When expressing a personal opinion in the past, use “must have”.


  • He must have been here. Something must have happened.

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