"The bridge is in the city."
Translation:Pons est in urbe.
That's not true when the verb is the copula "to be". The most common word order is with the "to be" in the middle of the sentence (or at the beginning)
But, even if your sentence hasn't the most common word order, it should be accepted as correct, so, next time, just report it, with the report button, and they'll add it to the database if the sentence is ok.
Style question. "Pons est in urbe" and "Pons in urbe est" are both correct, but which is better style? Why?
Please note: there are plenty of sentences where Duo puts esse (to be) at the end, as the best answer.
It seems like Duo prefers "esse in the middle" when two things are being equated (the bridge is my favorite bridge). For mere assignment of an attribute (the bridge is red, the bridge is in the city, etc.) Duo seems to use "esse at the end" more often - with this being an exception.