Modal verbs come before and modify the main verb in a sentence and help explain ideas like possibility, necessity, or obligation. Here are several modal verbs and their functions:
Might: Expresses uncertainty about the present or future, as in, "I might quit my job next month," or, "It might be cold out, so bring a jacket."
Can: Expresses ability or possibility, as in, "I can speak French and Spanish," or, "Students can get cheaper tickets at the movies." Also asks permission or makes a request, as in, "Can you come over tonight?"
Should: Expresses obligation, as in, "I should study for my math test," or probability, as in, "The package should arrive tomorrow, since I sent it last week." Also gives advice, as in, "I think you should go out with Jesse."
Must: Expresses necessity or obligation, as in, "I must go see my grandmother this weekend." Also gives strong advice, as in, "You must quit smoking now that you're pregnant."
Modal Verbs Grammar Quiz
Modal Verbs Lessons: