"He mixes the oil with spices."
Translation:Li miksas la oleon kun spicoj.
So wait, he mixes the oil with spices? Assuming he puts the oil in the pan first, the spices would be cooked on their own. Is this a common technique? I personally almost always cook southeast asian, but add spice like half way through. I do have this spiced oil I sometimes use which maybe reveals that his actions aren't so strange. I'm questioning my whole life now, please, give me some cooking advise here!
That's one thing about this course/language -- most grammatical mistakes in Esperanto are going to be off by one letter and interpreted as just a typo, when in fact, such answers probably should be rejected entirely. They should mark off when I forget the accusative ending or use an adjective instead of an adverb (bona/bone), etc. I wonder whether that's something they can control.
I’m wondering if, in the EN → EO translation exercise,
Li miksas la oleon kun la spicoj.
shouldn’t be acceptable, too—in cases like “he liked the boy’s lambs”, li ŝatis la ŝafidojn de la knabo — with one more la than the English has “the” — is preferred, but li ŝatis ŝafidojn de la knabo is accepted as an alternative. If the English were “He mixes oil with the spices” or “He mixes the oil with the spices”, then it would unambiguously be Li miksas oleon kun la spicoj or Li miksas la oleon kun la spicoj.
Still— although de of course has a deeper sort of existence in Esperanto compared with kun, if you think of them both as “just prepositions”, where la is allowable vs. required seems a little less clear-cut.
In English both "He mixes the oil with spices" and "He mixes the oil with the spices" are valid sentences, the first one referring to some unspecified spices, and the second to some spices which have already been specified in the context. For instance, a recipe might list olive oil, oregano, basil and paprika in the ingredients. Then it might say "Mix the oil with the spices". "La spicoj" would only be needed in Esperanto if the English were "the spices".