El «have to» se usa para decir que algo es necesario u obligatorio (se tiene que hacer).
Para formar frases con «have to» lo hacemos de la siguiente forma dependiendo de si las frases son afirmativas, negativas o interrogativas
AFIRMATIVAS [sujeto + have to + el verbo infinitivo]
I + have to + go
You + have to + go
He/she/it + has to + go (en afirmativas he/she/it va con «has to»)
We + have to + go
They + have to + go
NEGATIVAS [sujeto + don’t have to + verbo infinitivo]
I + don´t have to + study
You + don´t have to + study
He/she/it + doesn´t have to + study
We + don´t have to + study
They + don´t have to + study
INTEROGATIVAS [do + sujeto + have to + verbo infinitivo]
Do + you + have to + clear up?
Does + he/she/it + have to + clear up?
Do + we + have to + clear up?
Do + they + have to + clear up?
Ejemplos:
I have to work everyday. (tengo que trabajar todos los dias)
I don´t have to work everday. ( no tengo que trabajar todos los dias)
Do you have to work everyday? (¿tienes que trabajar todos los dias?)