"老师住在城市里。"

Translation: The teacher lives in the city.

[alfie.munding]

Why "the"?

[deactivated user]

Because this is the worst language tree on Duolingo? That's my guess. And opinion.

[Celticfiddleguy]

In different contexts this could be any of the following: "the teacher(s)", "(my/ our) teacher(s)", or "teachers".

[Melarish]

I think it would be 一个 if it was "a" city or "a" teacher

[IanMcFarla17]

In English it is idiomatic to speak of 'living in the city' (as opposed to 'the country'), even where a particular city is not named. To my ear it sounds less natural to say, 'The teacher lives in a city' than 'The teacher lives in the city', though both are possible.

[kuyaC]

Is 里 necessary?

[IanMcFarla17]

Specifically, what does 里 add (since we've been accustomed to using 住在 without any other prepositions for 'live[s] in')?

[SzymonRuci]

"The teacher lives in a city" is also correct and even more logical to me

[Ann55075]

and it is accepted now