EXPRESSING OBLIGATION: HAVE TO, MUST, SHOULD

EXPRESSING OBLIGATION WITH HAVE TO, MUST, SHOULD

“HAVE TO”

“Have to” es una expresión que se usa para indicar obligación o deber. Traduce “tener que” y está acompañada de un verbo sin conjugar o en infinitivo. Básicamente se debe conocer la forma del verbo To have, acompañado de sus respectivas variaciones, de acuerdo con los pronombres personales.

HAVE TO: PRESENT FORM
AFFIRMATIVE FORM	NEGATIVE FORM	QUESTION FORM
I have to write a poem for the Spanish class.	I DO NOT have to write a poem for the Spanish class.	DO I Have to write a poem for the Spanish class?
You have to ask for permission to your parents to go out.	You DO NOT have to read the newspaper.	DO you have to ask for permission to your parents to go out?
Marta has to prepare diner tomorrow.	Marta DOES NOT have to prepare diner tomorrow.	DOES Marta have to prepare diner tomorrow?
We have to visit some touristic places for the class of English.	We DO NOT have to visit some touristic places for the class of English.	DO we have to visit some touristic places for the class of English?
You have to repeat the exercises in which you made mistakes.	You DO NOT have to repeat the exercises in which you made mistakes.	DO you have to repeat the exercises in which you made mistakes?
They have to take the garbage out before the garbage truck arrives.	They DO NOT have to take the garbage out before the garbage truck arrives.	DO they have to take the garbage out before the garbage truck arrives?

“Had to” es la misma expresión usada para indicar obligación o deber, pero en tiempo pasado. Traduce “tenía que” y está acompañada de un verbo sin conjugar o en infinitivo.

HAD TO: PAST FORM
AFFIRMATIVE FORM	NEGATIVE FORM	QUESTION FORM
I had to write a poem for the Spanish class.	I DID NOT have to write a poem for the Spanish class.	DID I Have to write a poem for the Spanish class?
You had to ask for permission to your parents to go out.	You DID NOT have to read the newspaper.	DID you have to ask for permission to your parents to go out?
Marta had to prepare diner yesterday.	Marta DID NOT have to prepare diner yesterday.	DID Marta have to prepare diner yesterday?
We had to visit some touristic places for the class of English.	We DID NOT have to visit some touristic places for the class of English.	DID we have to visit some touristic places for the class of English?
You had to repeat the exercises in which you made mistakes.	You DID NOT have to repeat the exercises in which you made mistakes.	DID you have to repeat the exercises in which you made mistakes?
They had to take the garbage out before the garbage truck arrived.	They DID NOT have to take the garbage out before the garbage truck arrived.	DID they have to take the garbage out before the garbage truck arrived?

En estas páginas encontrarás información adicional: You will find additional information here:

· http://www.englisch-hilfen.de/en/grammar/have_to.htm

· http://www.englishclub.com/grammar/verbs-modals-have-to-must-not-1.htm

· http://www.edu.xunta.es/centros/iesblancoamorculleredo/system/files/Have+to.pdf

· http://www.perfect-english-grammar.com/modal-verbs-of-obligation.html

“MUST”

“Must” se usa para indicar que estamos seguros de algo: hacemos una deducción lógica basada en evidencia o razón claras.

There's no heating on. You must be freezing. ðNo hay calefacción. Te debes estar congelando.

You must be worried that she is so late coming home. ðDebes estar preocupado de que ella esté llegando tarde a casa.

I can't remember what I did with it. I must be getting old. ðNo puedo recorder lo que hice con eso. Me debo estar envejeciendo.

It must be nice to live in Florida. ðDebe ser maravilloso vivir en la Florida.

“Must” también se usa para expresar una obligación fuerte. Cuando usamos “Must” generalmente quiere decir que alguna circunstancia personal hace la obligación necesaria, y el hablante casi siempre valida dicha obligación.

I must go to bed earlier. ðDebo ir a la cama temprano.

They must do something about it. ðEllos deben hacer algo al respecto.

You must come and see us some time. ðDebes venir y vernos algún tiempo.

I must say, I don't think you were very nice to him. ðDebo decirlo, no creo que le hayas caido bien.

“SHOULD”

“Should” expresa una opinión personal y es mucho más liviano y más personal que “Must” o “have to ”. Generalmente está acompañado de “pienso”

I think they should replace him. ðPienso (creo) que ellos deberían reemplazarlo.

I don't think they should keep the contract. ðNo creo que ellos deberían mantener el contrato.

Do you think we should tell her? ð¿Piensas que deberíamos decirle (a ella)?

EN RESUMEN

1) “Have to ” se diferencia de “Must” en que “Have to ” indica que alguien nos ha impuesto una condición.

2) “Do not have to ” implica que no es necesario cumplir con la obligación.

3) El pasado de “Must” es “Had to ”.

4) El futuro simple de “Must” es “will have to ”.

5) “Should” es más un consejo que una obligación.

En estas páginas encontrarás información adicional: You will find additional information here:

· http://www.aulafacil.com/Ingejerc/Lecciones/Lecc26.htm

· http://www.englishgrammarsecrets.com/should/menu.php