- Ella habló por teléfono con su mamá.
- Ella siempre hablaba por teléfono con su mamá.
Both examples show the past tense but with different aspects: they have two different meanings. Which example shows a perfectly complete action in the past? Which one shows an action in progress that might have occurred multiple times?
If you guessed that the preterite represents the perfect aspect and the imperfect represents the progressive aspect then you are correct!
The first sentence shows that she talked on the phone at either a specific time or it was a completed finished action. Whereas the second sentence shows a repeated or habitual action in the past that was never completed. So the next time you’re stuck on preterite versus imperfect, think about the concept of “aspect” and what meaning you are trying to convey.