For this case we can translate the sentence given as:
My dad______________ at school.
We must fill in the blank with the proper conjugation of the verb to be.
In indicative of the present tense we have:
My dad is at school.
In indicative of the imperfect preterite time we have:
My dad was at school.
In indicative of the future tense we have:
My dad will be at school.
ANswer:
Mi papá esta en la escuela.
Mi papá estaba en la escuela.
Mi papá estará en la escuela.