Mi hermano (tomar) ____________ un café en la mañana.
Translation:
My brother (to drink) [blank] a coffee in the morning.
The blank must be filled with tomar conjugated for the subject (mi hermano) in the preterite tense. The subject is third-person singular.
Preterite tense is used to speak about events that happened in the past that have come to an end (not continual actions - those would be imperfect). Thus the sentence must become
My brother drank a coffee in the morning
in Spanish.
The correct conjugation is tomó.
Answer:
Mi hermano tomó (tomar) ____________ un café en la mañana.