"We never used to walk on that street."
Translation:Nós nunca costumamos caminhar naquela rua.
In my opinion "Nós nunca caminhávamos naquela rua" is a better translation. In English "never used to ..." means "did not ever ...", but I think "nunca costumávamos ..." means something like "did not usually ..."
I just asked my host-grandmother (I'm on exchange in Brazil) about this, and she said both sentences mean the same thing but she prefers the form with costumamos. This is in Rio Grande do Sul, btw.
The exercise has 3 options for the English "We never used to...: 1. Nunca costumamos... 2. Nunca costumavamos... 3. Nao costumamos. I chose #1 and got it right. Are you saying that only 2 is right in this context?
I still keep my point. Nós nunca costumamos = we don't usually / we are never used to...
This sentence is confusing, and I'm not sure I understand what the Portuguese really means in English. This is made particularly difficult because it includes a negative word, "never". I really think this sentence should be moved into a section on imperfect verb forms, but maybe I'm wrong.
Paulenrique, I also think you might have meant "We never used to", rather than "We are never used to." (If so, then the Portuguese makes more sense, to me at least.)
"We never used to" and "We are never used to" don't mean the same thing in English.
"We never used to" is a type of habitual past form (I may be using the wrong grammatical term, but it means we never did it on a regular basis in the past, but maybe we do now). It's often translated by an imperfect verb form into other languages (for those that have it), similar to, "We were never [doing whatever]", although to say "We were never walking on that street" is a really weird sentence in English (Maybe in response to someone accusing you of always walking on that street, when what you mean is a more emphatic form of "We were NOT walking on that street!")
To be used to something means that it's something you've seen before, maybe done before, and that you accept as normal. "We are never used to" sounds weird in English. You would more likely say, "We were never used to," or even "We never got used to..."
At this point, I'm confusing myself and going on for too long, but this page might help: http://tinyurl.com/op7za7e
When I did the exercise there was no option with "costumávamos" - the imperfect tense which is needed here.
I had it as multiple choice and imperfect was not offered. This same sentence in Portuguese, with the preterite, was marked wrong when I translated it as "used to walk." Duo's approved translation that time was "we use to walk" (which I don't believe is ever correct in English under any circumstances).
Now, Duo says "used" is correct.
For a discussion (including a reference from NOAD) which confirms that "we use to" is not correct English, see: http://english.stackexchange.com/questions/30035/i-use-to-or-i-used-to
Used to is correct for affirmative sentences.
Didn't use to is correct for negative sentence.