If you were to say "Yesterday, I saw a dog" would you use the imperfect tense of "to see" or would you use the preterite tense?
If you know why then could you explain it to me? Or just translate it. Thanks!
Welcome to the forum!
I can explain the difference between the preterite and the imperfect in a nutshell, and then as you advance in Spanish you will learn more in addition to the "nutshell".
Generally speaking, the preterite answers the question "what happened?", whereas the imperfect tells you what was going on (background), used to be, always was, etc.
Therefore, "yesterday I saw a dog" tells you what happened. "Ayer vi un perro".
I hope this helps!
The way it was explained to me was preterit is a point on the historical timeline. Imperfect is a segment on the historical timeline.
So "I went to school yesterday" would be "Fui a al escuela ayer" but if you want to say "I went to school when I was young" it would be "Iba a la escuela cuando era joven."
Edited to add: Lesson 2.10 discusses the preterit vs. imperfect.