Modal Verbs

Advice

Should -------------------------------------------------------deberías

 ex: You should study harder---------------deberias estudiar más

Ought to ---------------------------------------deberías

ex: You ought to study harder

Ability

Can --------------------------------------------------------------puedo

ex: I can write with my left hand

Could ----------------------------------------------------------- podía

ex: When I was young I could run very fast

Be able to -----------------------------------------------ser capaz de 

ex: In the future I will be able to speak English correctly

Permision

Can ------------------------------------------------------------puedo

ex: Can I open the window?

Could----------------------------------------------------------Podría

ex: Could I open the window?

Be allowed to-------------------------------------------- permitirse

ex: It is not allowed to smoke in public places

Possibility and cartainity

Could --------------------------------------------Podria, puede que

ex. John could be at the doctor

Might---------------------------------------------------- debe/quizás

ex. John might be at the doctor

May ------------------------------------------------------------ quizás

ex. John may be at the doctor

Must------------------------------------------------------- seguro que 

ex: John must be at the doctor

Can't------------------------------------------------ no puede ser que

ex: John can't be at the doctor

(NOT couldn't, mustn't)

Prohibition

Mustn't -------------------------------------------------------no debes

ex: You mustn't eat junk food

(NOT must)

Obligation

Have to ------------------------------------------------------tienes que

ex: I have to buy milk

Don't have to -----------------------no tines que (no es necesario que)

ex: You don't have to come if you don't want to

Need to ------------------------------------------------------- tienes que

ex: I need to buy milk

Needn't--------- no tienes que

ex: You needn't come if you don't want to

must------------ debes. 

ex: You must come to class. 

(NOT mustn't)