Final answer:
To translate 'I studied with Juan for three hours' into Spanish, use the preterite tense: 'Estudié con Juan durante tres horas.'
Step-by-step explanation:
Spanish, like many languages, has a variety of verb tenses that convey different times, moods, and aspects of actions.
To translate the sentence 'I studied with Juan for three hours' into Spanish, you would use the preterite tense. The preterite tense is used to talk about completed actions in the past. In this case, 'studied' is a completed action, so we would use the preterite tense. The Spanish translation would be 'Estudié con Juan durante tres horas.'