"It is not Peter living in the room, from which the pretty kindergarten teacher comes out."
Translation:Abban a szobában nem Péter lakik, amelyikből kijön a csinos óvónő.
The point is, whatever is denied must follow the word "nem".
Nem Péter - not Péter
Nem lakik - does not live (there)
So, the first one says that it is not Péter, and the second one says that he does not live there. It sounds as though he lives at several places but not at this place.
I believe that 'ami' is used to refer to the entire previous clause, or to refer to something 'unnamed' On the other hand, 'amelyik' is used to refer to a named or specific noun.
Compare 'I wear what I work in' (use 'ami') to 'I wear the clothes that I work in' (use 'amelyik').
A question regarding the whole skill - abban a szobában, or azokra a székekre etc - i always thought i should translate it with "That/those" rather than simple "the"... but was marked incorrect a few times because the correct solution required "the" .... so how is that reconciled with the skill a few steps back where we first learnt abban, annál, ebben etc? Is it something different here because i use the second sentence? Thanks!
In my opinion, translating that/those should be accepted by DL. The reason it is not has to do more with English than with Hungarian.
The words this/that are demonstratives, which means that they are used to point something out. However, sometimes you modify or qualify a noun with a following clause. In this DL exercise, for example, the noun 'room 'is qualified as follows: '...room from which the teacher comes out.'.
That qualifying phrase also has the effect of pointing out or emphasizing the noun that it qualifies. So to also use the demonstrative 'that' in front of the noun feels, in English, like overkill. Consequently, native speakers tend to 'soften' the full phrase by using 'the' instead of 'that'.
It is not ungrammatical to say 'that' here, it's just that it sounds a bit hyperbolic and therefore not idiomatic.