"I wanted new shoes."
Translation:Yo quise zapatos nuevos.
I checked the vocabulary for quiere, and I think it is in the subjunctive tab? which, at this level has not been introduced before. Scroll down on the page to see some conjugation. Only later in the series are we to become enlightened, finally understand why Duolingo has been confounding us. I think.
Quería is the imperfect indicative of querer. I don't think there is a subjunctive past tense only present, imperfect and perfect. In this case, one would use the imperfect if a past action took place habitually. There is no indication that the new shoes were wanted habitually. For example: As I child, I always wanted new shoes. Here you would use the imperfect form.
This might help:
Though I don't think DL should quiz us on any grammar or vocabulary without introducing it to us first. I cheated on this particular item by going to look at all the conjugation possibilities for "querer" - I hate to lose a heart on something I haven't seen before.
I said only one (queria - the imperfect) was correct, and was wrong. I cannot imagine "wanting new shoes" as a "happened once" situation, so do not see why the preterite would be accepted. The preterite is used for actions in the past that are seen as completed. Use of the preterite tense implies that the past action had a definite beginning and definite end. [From: http://www.studyspanish.com/lessons/pretimp1.htm]
It seems it would be preterite (quise) in a context such as this: "Yesterday I walked past a shoe store and suddenly realized I wanted new shoes." But, I think what lomagna says below is true ("querer in preterite means to try and fail") and so agree, "quise" seems a bad translation in this exercise. Unless it's "Yesterday I walked past a shoe store and suddenly realized I wanted new shoes but didn't have time to shop". (I feel like I'm digging myself very deep here! :)
According to this, querer in the predicate can mean wanting but failing but can also mean just "wanting" in the past. Example given is "quise comer un taco". http://spanish.about.com/od/verbtenses/a/past_tenses_with_certain_verbs.htm