Hi, ThanKwee! Context, or rather the lack thereof, is the bane of Duolingo. My observation is that DL has indoctrinated us to interpret the definite article as "THE" in front of the noun whether generality or not and more-or-less successfully (Thanks to Sitesurf) helped us understand that "des" is the plural of "un" (if it's not used in the sense of "of the"). There may have been some exercises that applied these principles inconsistently but I can understand how some are puzzled about something that was pounded into us is now seemingly ignored. No reply needed. Keep up the good work!