Preterite and imperfect, both verbs can be used in Spanish depending upon the meaning.
Take a look at these examples:
Martha corrió por dos horas.
(Martha ran for two hours)
Martha corría todas las mañanas.
(Martha ran every morning)
The preterite is more specific whereas the imperfect tells us in general when an action took place.
The preterite is used for:
The completion of past actions or states.
The beginning and the end of past actions.
The imperfect is used for:
Actions and states in progressive at some focused point in the past.
Habitual past actions.
Repetitious past actions.
(I moved to New York in 2012)
Narrate a sequence of events:
(First, I wento to Pedro´s house, then I went to school, and I arrived home at three in the afternoon)
The beginning or the ending of an action or a state:
A habitual action in the past:
(My family and I went to church every Sunday)
*Descriptins in the past:
(When I was a little girl, I had straight hair)
To describe physical, emotional and mental states:
When you describe what people were doing or used to do. When you describe what something or someone look like use the IMPERFECT TENSE.
However, the stories that happened within these settings happen in the PRETERITE. The preterite will interrupt the action that was going on.
(My friends watched the television, when the police arrived)
The second component of the sentence is the preterite that interrupted the imperfect, the action that was going on.
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