Have To

Have to (objective obligation)
We often use have to to say that something is obligatory
Structure of Have to
Have to is often grouped with modal auxiliary verbs for convenience, but in fact itis not a modal verb. It is not even an auxiliary verb. In the have to structure, "have" is a main verb. The structure is:
subject + auxiliary verb + have + infinitive (with to)
Look at theseexamples in the simple tense:
| subject | auxiliary verb | main verb have | infinitive (with to) | |
+ | She | | has | to work. |   |
- | I | do not | have | to see | the doctor.|
? | Did | you | have | to go | to school? |
Use of Have to
In general, have to expresses impersonal obligation. The subject of have to is obliged or forced to act by a separate,external power (for example, the Law or school rules). Have to is objective
We can use have to in all tenses, and also with modal auxiliaries. We conjugate it just like any other main verb. Here are someexamples:
FORMED: with have to + infinitive verb: see the different forms below.

AFIRMATIVO
I have to
you have to
he/she/it has to
we have to they have to

NEGATIVO
I don´t have to
youdon´t have to
he/she/it doesn´t have to
we don´t have to
they don´t have to

INTEROGATIVO
do you have to
does he/she/it have to
do we have to
do they have to


Tienen que (obligaciónobjetiva)
Utilizamos a menudo tienen que decir que algo es obligatorio
Estructura de tener que
Tiene que se agrupa a menudo con los verbos auxiliares modales por conveniencia, pero en realidad no esun verbo modal. Ni siquiera es un verbo auxiliar. En el haber de la estructura, "han" es un verbo principal. La estructura es:
sujeto + verbo auxiliar + tienen + infinitivo (con to)
El uso deHave to
En general, tienen que expresa obligación impersonal. El tema del que está obligado o forzado a actuar por un poder externo separado (por ejemplo, las normas de la Ley o de la escuela)....