Why is "soit des vacances soit du travail" wrong as a translation of "either holiday or work"?

Bonjour Jose, Was there a question involved with your post? I do not find that type of question in the lesson.

The correct answer is "soit les vacances soit le travail". Here you are talking about vacation and work in general terms: either vacation (in general) or work (in general). "Des vacances" uses the partitive "de" and refers to (some vacations). Similarly for "du travail". -- Chris. (not a native speaker)

The question is when do you use, for example, des vacances instead of les vacances, or du travail instead of le travail.   In one of the examples we had du fromage but un dessert.