Must es un verbo modal que expresa la obligación de hacer algo.
Como todos los modales, va seguido de otro infinitivo sin “to”.
Afirmativa
I must work
You must work
He/she/it must work
We must work
You must work
They must work
Interrogación respuesta breve + -
Must I work? Yes, I must No, I mustn´t
Must you work? Yes, you must No, you mustn´t
Must he / she / it work? Yes, he / she / it must No, he / she / it mustn´t
Must we work? Yes, we must No, we mustn´t
Must you work? Yes, you must No, you mustn´t
Must they work? Yes, they must No, they mustn´t
Negación: Mustn´t está explicado en otro apartado de los Verbos Modales, por la diferencia de significado con must. · Must también se utiliza para expresar una conclusión:
- The light is on. He must be at home.
- It´s very windy and cloudy. It must be cold.
- He´s got a lot of white hair. He must be over 40.
- There´re pieces of glass on the road. There must have been an accident.
Must sólo tiene forma de presente. Por ello, para cualquier otro tiempo se utiliza have to:
- I´ll have to work next Sunday.
- She had to clean all the house.
Have to indica obligación, al igual que must.
Afirmativa
I have to work we have to work
You have to work you have to work
He/she/it has to work they have to work
Interrogación respuesta breve + -
Do I have to work? Yes, I do No, I don´t
Do you have to work? Yes, you do No, you don´t
Does he / she / it have to work? Yes, he / she / it does No, he / she / it doesn´t
Do we have to work? Yes, we do No, we don´t
Do you have to work? Yes, you do No, you don´t
Do they have to work? Yes, they do No, they don´t -
También puede utilizarse have got to, que es algo más informal.
Existe una pequeña diferencia de significado entre must y have to:
Must indica una obligación que se impone uno mismo, más que las circunstancias:
- I must study for the exam.
- He must work more to have enough money.
Have to, en cambio, expresa una necesidad impuesta por las circunstancias externas:
- She has to get up at 7 every morning. - We have to work till 6 on Mondays.
Don´t have to expresa que no es necesario u obligatorio hacer algo. forma completa forma contraída
I do not have to work I don´t have to work
You do not have to work you don´t have to work
He/she/it does not have to work he/she/it doesn´t have to work
We do not have to work we don´t have to work
You do not have to work you don´t have to work
They do not have to work they don´t have to work
Ejemplos:
- You don´t have to do the shopping. I´ll do it tomorrow.
- I don´t have to go to school at weekends. - They don´t have to wash by hand because they´ve got a washing machine.
