Num is used when an answer of 'no' is expected. Conversely, you may see nonne when an answer of 'yes' is expected.
Question: Corinna doesn't live in Rome, does she? (Num Corinna Romae habitat?), Expected Answer: No, she doesn't.
Question: Corinna lives in Rome, doesn't she? (Nonne Corinna Romae habitat?), Expected Answer: Yes, she does.
In my opinion asking "Doesn't Corinna live in Rome?" is expecting a no answer just as much as Duolingo's "Surely Corinna doesn't live in Rome?" I'd use either of those interchangeably, e.g. when I had thought she lived in Rome, and just heard that she lived in Venice. No, actually I'd use the first in that case, and the second when I thought she lived in Venice and just heard she lived in Rome. Ha ha, writing out all these scenarios has convinced me that the DL team is right, and SenorDustin, VinniePine and I are wrong. It's subtle though! I think Moopish's tag question *"Corinna doesn't live in Rome, does she?" best expresses that the expected answer is no. I'm giving them a lingot.
I suspect a good amount of it in English is really just how emphasize it in English. The examples I used were largely based on what I remember from how it was explained when I took some Latin courses.
I honestly don't think about this kind of differentiation in English much. Very interesting to see how you viewed the differences.
"Surely Corinna does not live in Rome?" sort of covers it, but for me a much better translation is: "Corinna doesn't live in Rome, does she?" -- in the sense that I don't believe she does; will you confirm that for me? (I'm inviting you to reply: "That's right; she doesn't").
The opposite circumstance would be for me to ask "Nonne Corinna Romae habitat?" = "Corinna lives in Rome, doesn't she?" (I want you to tell me: "That's right; she does").
My answers with "That's right" were to show that the responder is agreeing with the questioner. Here are the answers using "yes/no":
C. doesn't live in Rome, does she? / No, she doesn't.
C. lives in Rome, doesn't she? / Yes, she does.
But I'd better stop now. This is turning into an English lesson!
Sorry, I should have worded that to make clear that I was looking for the Latin answers:
"Num Corinna Romae habitat?"
"Nonne Corinna Romae habitat?"
If you answer Ita, or Minime, or yet another answer, what does that imply in each case? Do you answer the "Corinna Romae habitat?", ignoring the speaker's expectation, or rather the opposite?
- 1 Does Corinna live in Rome? Yes, Corinna lives in Rome.
- 2 Does Corinna live in Rome? No, Corinna doesn't live in Rome.
- 3 Corinna doesn't live in Rome? Indeed, Corinna doesn't live in Rome.
4 Corinna doesn't live in Rome? Rather, Corinna does live in Rome. (Does English really have no better reply for this one?)
5 Nonne Corinna Romae habitat? Ita ...
- 6 Nonne Corinna Romae habitat? Minime ...
- 7 Num Corinna Romae habitat? Ita ...
- 8 Num Corinna Romae habitat? Minime ...
So, what are the answers: Does one indeed use "ita" and "minime", and what would agreement or disagreement signify?
From Lewis and Short via the Perseus Project: RomaRome, the mother city (Show lexicon entry in Lewis & Short Elem. Lewis) (search)
romae noun sg fem gen romae noun sg fem dat romae noun pl fem voc romae noun pl fem nom
It appears the makers of this module like to use the genitive to denote location as with 'Ea Novi Eboraci studet.' In another example. I believe this use of the genitive to be wrong.