Translation:Her behavior at the party was far from being perfect.
It doesn't really change the meaning from "está" since whenever you can use "queda" you can use "está" but not the other way around. "queda" is used to ask for the location of places, buildings, houses, schools, hospitals, etc. For example:
¿Dónde queda el hospital?
¿Dónde queda la escuela?
¿Dónde queda la estación del tren?
"Está" as I said can be used in any situation where you use "queda", for places and objects.
¿Dónde está la escuela?
¿Dónde está el hospital?
¿Dónde está la estación del tren?
¿Dónde está el gato? but never ¿Dónde queda el gato?
"Queda" basically means "to be situated", to make it more understandable, so ¿Dónde queda el hospital? means Where is the hospital situated? or in more natural terms Where is the hospital?
Well, this is supposed (I doesn't really feel like it) to be Spain Spanish and up to where I know in Spain they always use "estar", they do understand "quedar" but they don't use it, just as we understand their usage of "vosotros" but do not use it.
As for what your girlfriend said, yes but not in just any context. For example let's say I went to my aunt's house with my cellphone, I used it there, left it on the counter and went home. When at home I start looking for my cellphone, that's when I remember that I left it at my aunt's house and say "Oh, mi celular se quedó en casa de mi tía." that's the way you use it to mean that you left something behind by accident. or I might ask someone "¿Has visto mi celular?" and they respond "Se quedó en casa de tu tía." Your example needs an interrogative adverb (cómo, cuándo, cuánto y dónde.) to make sense:
¿Dónde se quedó mi zapato?
¿Dónde se quedaron mis zapatos?
As I said you don't just use it to ask the location of any object, but rather an object that you had and unconsciously left somewhere. Note that if you use reflexive it sounds better. Can't say that "¿Dónde quedaron mis zapatos?" is wrong because I'm not really sure, it doesn't sound so good to me but is makes sense and does not sound so wrong either.
I disagree. I think "Your comportment at the party was far from being perfect." is a fine English sentence. Too bad comportment as a translation for "comportamiento" is not accepted yet. You think that would be the first translation, but I guess Duo really wants us to earn our keep.
I am going to split the difference between Librasulus and Isaiah: "far from being perfect" is good (one might even say perfectly good) English, but the word "being" is unnecessary verging on awkward, and the sentence is more natural without it.
I also agree with Monica Greene that in this context (not all contexts) "conduct" is a good substitute for "behaviour".
If one speaks English, and lives in the United States (or in my case, in Mexico), the word "fiesta" does not need to be translated. It is part of the English language. An apt comparison would be the word "patio." How might I translate that into English? I wouldn't know a better word.
It's not a gender issue. It's singular v. plural.
Su = plural with singular noun
Sus = plural with plural noun
I'm guessing that "their behaviors" would be the implied meaning (everyone's behaviors), not a collective, single behavior, meaning that the sentence would change to:
Sus comportamientos en la fiesta estuvo lejos de ser perfectos.
But that's just a guess.
It should accept "their behavior", su works for singular or plural, and nothing in the sentence indicates a feminine subject.
Daveduck, even if referring to multiple subjects you should use "comportamiento", and if you use "comportamientos" you need to change "estuvo" to a plural too. "Sus comportamientos en la fiesta estuvieron lejos de ser perfectos."
No, the gender of the noun cannot change. The adjective is changed to match the gender of the noun. However, I don't know why it was translated as "her" behaviour. 'Su' can also be translated to mean 'his' or 'your', and without clarification there is no way to know which translation is intended.