"These were the final letters."
Translation:Estas fueron las cartas finales.
I find that "último" usually comes before the noun. Try "las últimas cartas".
That was my answer, but it was disallowed. I think it's an acceptable translation though.
In front of the noun would mean the last letters, after the noun would mean the ultimate letters (aka the best ever). I think :)
Whats wrong with estuvieron. Final letters isn't a characteristic but a state.
My guess: because it's about the fact / existence / event of the letters, not the state of the letters relative to other states of the same letters. Nor the state of anything else, because there is no other topic in this sentence - the verb (fueron) refers to the letters.
Way too complicated. I've noticed a lot of situations that need to be memorized. And the real test is conversation. I'm sure i would be understood if i used estuvieron.
You did ask though. And it's not about memorisation, it's about understanding when to use ser vs estar so you don't have to memorise. The effort involved is not that great and makes things a lot easier going forward in my experience.