Ser vs. Estar, Preterite vs. Imperfect

Question

If I wanted to say that a "city was surrounded at the center of a lake", would I use Ser or Estar and preterite or imperfect? And why. Thanks!

Answer 1

You always use estar for position or where things are located. And I would use imperfect because preterite is more for specific events with a clear beginning and end (I did all of my tasks. Hice todas de mis tareas.) and impefect is for events with no clear beginning and end. por ejemplo: la cuidad estaba rodeada al centro del lago.