The explication of the modals uses in english

1. MODALS
VERBS

2.  Yes
 Must: Deber(Obligación)
 Have to: Tener que
Example: You must finish your work.
You have to work harder.
 No
 Don’t have to: No tener que
Example: You don’t have to take an
umbrella, it isn’t going to rain

3.  Could: Podía/Podría
 Might: Podría/Puede que
 May: Quizás/Podría
Example: You could be wrong. I may visit
Susan on Monday. They might be waiting for
us at the station.

4.  Yes:
 Should: Deber(Consejo)
 Ought to: Deber(Consejo moral) No se usa
Example: You ought to visit your grandmother
more often. We should go to sleep.
 No:
 Shouldn’t: No deber(consejo)
Example: You should not say that

5.  Must: 100% sure
 Should: Quite sure
Example: She should be doing her
homework. Julia must be in Paris by
now.

6.  Yes:
 Can: Poder
Example: You can sit here if you like.
 No:
 Mustn’t: No deber
 Can’t: No poder
Example: Mr. Williams mustn’t smoke
here. You can't tell me what to do.