"Fuimos testigos del accidente."
Translation:We were witnesses of the accident.
The equally normal expression is witnesses to the accident, witness is a quasi legal expression and really needs to not of. You can be an observer of the accident and then a formal witness to the accident.
Just when i think i understand FUE vs ESTUVO, I realize I do not. Why cant ESTUVIMOS be used in the above sentence? We were witnesses of the accident, but now we arent anymore. Isnt that temporary/conditional? Confused and need help. Gracias