- 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 various times? If you guessed that the preterit represents the perfect aspect and imperfect the progressive aspect then you are correct! #1 shows that she talked on the phone at either a specific time or it was a completed finished action. Whereas #2 shows a repeated or habitual action in the past that was never completed. So the next time you’re stuck on preterit versus imperfect, think about aspect and what meaning you are trying to convey.