Apuntes 21-22 de octubre El pretérito y el imperfecto The preterite and the imperfect are both past tenses, but they express different types of actions and are not interchangeable.
Uses of the preterite Expressing actions that are viewed by the speaker as complete. Javier se torció el tobillo. Javier sprained his ankle.
Expressing the beginning or ending of a past action. El concierto empezó a las siete. The concert began at seven o’clock. Los estudiantes terminaron el libro. The students finished the book.
Narrating a series of events. El hombre cenó, se duchó y se acostó. The man ate dinner, took a shower and went to bed.
Uses of the imperfect Describing events in progress in the past. La enfermera le tomaba la temperatura al paciente. The nurse was taking the patient’s temperature.
Expressing habitual actions in the past. Cuando Paco era pequeño, jugaba al escondite con los vecinos. When Paco was little, he used to play hide-and-seek with the neighbors.
Describing physical and emotional states and characteristics. Me sentía enfermo. No quería ir a la escuela. I felt sick. I didn’t want to go to school. Mi hermano era alto y fuerte. My brother was big and strong.
The preterite and imperfect are often used together. The imperfect expresses what was going on and the preterite expresses what happened when the activity was taking place. Mi hijo esquiaba cuando se rompió la pierna. My son was skiing when he broke his leg.