"I like to eat, but you eat my meal."
Translation:J'aime manger, or tu manges mon repas.
I was wondering that, too. There was a similar situation in German, where a less common word ("mitunter") was taught before/instead of a more common one ("manchmal.") Beginning learners will assume they're learning natural (not formal or "fancy") language, unless you clue them in.
I think "donc" is more like "thus/therefore" ("Je pense, donc je suis.")
I just looked up "or"; the first meaning is "gold" of course, but the 2nd: 2(a) now; as it happens, in fact (rare); "or donc"=thus, therefore So, there's also "or donc"! But "or" by itself is rare, according to this dictionary.