I think THEY is just emphasised. e,g, "Those guys, where do they work". I don't think I often here people emphasise "they" in English, but I would expect more likely "And you, where do you work?".
Also "loro" explicitly refers to people, you can clarify that you are not saying something like "where do they work?" and referring to Travel Passes (objects) for example.
the participle agrees only if essere is used, not avere - " i ragazzi sono andati" , "le ragazze sono andate" (agrees in singular too, but not showing it... haven't figured out accents when writing here yet)... but " i ragazzi hanno mangiato", and "le ragazze hanno mangiato". As for the position of dove - sorry, only level 11, still in the dark there!
Perhaps if you could provide an example of a good sentence which uses where at the end, it would help me expand my thinking on this topic.
I do know a usage, but the "where" is not really part of the structure of the sentence, where someone meant to ask "Where did you..." but instead blurted out a simple statement or question, then added the "where" at the end to finish the thought - a one word emphatic, such as: "You forgot the kids again --- where?"
Not certain I can provide a "good" sentence, it isn't something I would likely use in my graduate thesis for English. However, as you point out, it gets tagged on the end for emphasis at times. Asking "Where do you work?" is likely a true question. "You work WHERE?" would more likely be SAID if the speaker already knew that answer, and was expressing shock or disbelief. It might only be WRITTEN in bad novels, if ever.
When I wrote that answer, I was not thinking about proper English grammar (something that Duolingo often ignores as well). I was attempting to translate a statement as literally as possible, since that seems to be a safe way to do it within the confines of this program. I also did not suggest Duo SHOULD accept that answer, by the way. Mostly I was wondering if the odd (to me) word order signified something comparable to the emphasis discussed.
"where have they worked" was accepted Feb 11 2018.
Did you copy and paste your answer here? Sometimes answer contain small errors which people don't pick up on, because they're not in the main part of a sentence which involves the particular module. I don't know how many times I've had a sentence rejected because I misspelled a verb by one letter, and it could not be accepted as a mere typo, because the misspelling changed the meaning of the verb or was the wrong conjugation because of that misspelling, e.g., "she work" instead of "she works".
That depends on what you mean by "proper". Several people have suggested a that the placement of loro is to emphasize "they", and suggested that punctuation would help. A year ago I commented that "this would make more sense if it were "Loro --- dove hanno lavorato?""
There doesn't appear to be a different explanation here for this odd word-order. I don't think seeing it has taught me anything, and it only seems to have sown confusion in the ranks. I fully intend to forget it as soon as possible and never use it in a written sentence, ever.
Sometimes, Duo screws up. This appears to be one of those times.
In English, your sentence is not a question, but an incomplete statement. One usually reverses subject-verb order in English questions, so "Where have they worked?" would be a valid question.
To be a complete sentence, your answer is a "clause" (part of a sentence) which could be used for example as: "Where they have worked is unknown."
In some instances, a question can be expressed in English without reversing subject-verb, but this format is usually understood as a question through use of some form of emphasis, e.g., "You said that." (statement) vs. "You said THAT?" (question). Sometimes, the emphasis can be understood simply by the content and punctuation: "You said that?". In these two examples, "that" is functioning as a pronoun, not a conjunction.
[Note: A clause can form a complete sentence on it's own, or not. For example, "I did not know that he is a librarian." Here there are two clauses: "I did not know" and "he is a librarian". Each clause can stand alone as a complete sentence, but by using "that" as a conjunction, each is joined into a single sentence.]
I'm not certain what you're asking, but your question has piqued my curiosity.
If your sentence is meant to have the same meaning as the question, "Where did they work/have they worked?" then it would be Dove hanno lavorato?
To me, the order of words in your English example suggests a kind of emphasis on "where" - perhaps a disbelief that they worked in a particular place, or just seeking clarification about the place: For example, Person 1: "They used to work in the freak-show at the circus." Person 2: "They worked WHERE?" Or: "They worked in the White House in the Department of Bad Jokes." "They worked where?"
Anyway, I'd love to know how the Italians express that kind of emphasis.
I agree with malcolmissimo that "used to work" cannot be correct here because hanno lavorato cannot be translated into English signifying the imperfect or habitual past.
Going the other way, however, is not the same: Absent some sort of context which makes any one tense more apt than another, "Where did they work" could be translated using simple past/passato remoto, present perfect/passato prossimo, or imperfect/imperfetto.
IMO (In My Opinion), your sentence places emphasis on "where". The Italian appears to emphasize "they" rather than "where". Also, your sentence does not use English Present Perfect (the compound verb which uses either "to do" or "to have" as an auxiliary), and the Italian sentence does.
I don't think there is a good way in English to use the simple past to translate the Italian sentence. It's true that "did work" is a question form of "worked", but in this particular sentence, the emphasis in the Italian sentence on "loro" and the emphasis in your sentence on "where" makes your answer a mismatch to the Italian.
Duo has proven to be somewhat picky and fickle about how past tenses are translated. Sometimes simple past is a perfectly good translation for both present perfect and imperfect, and sometimes it's not. Who knows why.
That's just my opinion, of course. I would be interested to hear what others have to say about this point.