Grammar Point modal verbs
The modal verbs are can, could, may, might, must, ought to, shall, should, will and would. Dare, need, have to and used to also share some of the features of modal verbs. Modal verbs have only one form. They have no -ing or -ed forms and do not add -s to the 3rd person singular form:
He can speak three languages.
She will try and visit tomorrow.
Modal verbs are followed by the infinitive of another verb without to. The exceptions are ought to, have to and used to:
You must find a job.
You ought to stop smoking.
I used to smoke but I gave up two years ago.
Questions are formed without do/does in the present, or did in the past:
Can I invite Mary?
Should I have invited Mary?
Negative sentences are formed with not or the short form -n’t and do not use do/does or did.
You will find more help with how to use modal verbs at the dictionary entries for each verb.