"Marcus doesn't live alone, does he?"
Is this just a case of right answer, just not added yet? Or am I completely wrong? Because as I understand it, this is the implied "I assume the answer to this will be no" and the opposite would be "nonne" meaning "I expect the answer will be yes."
Agree, and have given you a lingot. This is an alternative I was taught at school:
... doesn't ... , does he? for num, and ... does ... , doesn't he? for nonne.
For my money the negative question at the end makes it much easier to remember which goes with nonne than the usual "expects the answer yes".
For modern British teenagers of course, the sentences would be:
Marcus lives at 'ome, innit? and Marcus don't live at 'ome, innit?
It's a bit ambiguous for me, as I don't know if a "no" would negate the assertion "Marcus does not live alone", and thus, mean a "Marcus lives alone", or mean that "no, you're right, he doesn't live alone".
It's probably because the answer will be ambiguous in my language, French?
"Tu confirmes que Marcus ne vit pas tout seul" -> oui. Yes, I confirm, he doesn't live alone. He lives with someone
"Marc ne vit pas tout seul, n'est-ce pas? -> Oui, he doesn't live alone.
But "no" is ambiguous.
Marc ne vit pas tout seul? Non. (non he doesn't live alone, or non I disagree with you, he lives alone?)
A bit ambiguous when saying a "non" alone. Is it the case in other languages too?
French would reply "si" if a negative sentence is positive in reality.
Marc ne vit pas tout seul, c'est bien ça?
Si! (si: Marc lives alone).
It's a little more than that. "Surely Marcus does not live alone?" implies disbelief (perhaps even shock), probably because I don't think Marcus should be or would be living by himself.
It also implies that I have some slight reason to believe that he might be living by himself, and I have trouble with the idea that he could possibly be living alone.
Preceding a statement with num turns it into a question to which you expect the answer to be no.
The question "Surely Marcus lives alone?" implies that you think he does live alone, so you are expecting the answer yes. To form the question this way you use nonne instead of num, so Nonne Marcus solus habitat?
Another way to do this in English is to tack "does he?" or "doesn't he" onto the end of your statement. So "Marcus doesn't live at home, does he?" (expects no, use num) and "Marcus lives at home, doesn't he?" (Expects yes, use nonne). This English form of interpreting num and nonne is used in some Latin textbooks but the course creators don't seem to like it, at least at present.
Marcus solus habitat without the preceding num is simply a statement: Marcus lives alone.
Num Marcus solus habitat? becomes a question that expects the answer no, therefore: Surely Marcus doesn't live at home?
A million years ago at school I was taught to translate this as: Marcus doesn't live at home, does he? but the contributors do not seem to accept this, at least they didn't when I was working through the tree.
As it should be. The answer you suggest is not good English. If you begin your sentence with "Surely," then you cannot move the verb into second position: you have to leave the rest of the sentence in the same order it would ordinarily be in as just a plain sentence. It's not really a question.
For a main clause in English to be a true question (the kind that is a question at the syntactic level and not just as a matter of intonation), it must begin with either a verb or a question word/phrase (who, which one, how many, where else, etc.) immediately followed by a verb. Your sentence violates English syntax.
For one thing, you're missing an 's' on 'Marcus.' But also, it is not normal in Latin to front the verb like this in a construction involving 'num.' You can just add 'num' to the beginning of a sentence in Latin and get a good question out of it; no need to move the verb around. If you're learning Latin you need to get used to the word orders that are actually common in Latin.