"During a period of a month"
Translation:Under en period av en månad
Same here, i've encountered it in other lessons also. I made all the time lessons in a streek and then strengthened them - there were new words that are not (color)marked aswell. It is not realy a prolem for me, and i am telling people that i send to duolingo that it is that way, however you might want to either "fix" that or make it clear.
Doesn't sound right to me, I would interpret that as "during a part of a month". Also if you do a google search using the term "under en del av en månad" you get >20 000 search results whereas "under en del av en månad" gives you 7 search results. If you wan't to replicate this, remember to include to quotation marks to search for an exact match.