LOL, can't tell if you're being funny but it would seriously keep all of these boards a lot easier to read if people would just look at previous answers. This one isn't so bad, but some of them have the same question being asked literally dozens of times (like why "the breakfast" in French is "le petit dejeuner" and not just "le dejeuner." Spoiler alert -- because that's how the French say it!!!).
I also put in "Mondays i do not work" and it was counted as wrong. I could have put "On Mondays I do not work" but in English its the same exact sentence. There was no option to put "On Monday I do not work", which it seems according to some of the answers above is what it should have been since the first word was il and not i... For me this was not a verbal question, but a choice of words to put together to form a sentence, so something is not right here...
In all these comments, one finds that no one has asked the obvious question: Where is the word "On" in the Italian version? If the Italian speaker wanted to say "on" then one might expect that preposition at the start of the sentence (that is the function of a preposition; it's pre-positioned).
Whoever might claim that "On Mondays ..." is just a common or colloquial way of translating "Mondays ..." would need to explain why omitting the "on" would not similarly be a common or colloquial way of expressing the idea of this sentence.
So it's obvious to a native English speaker that it doesn't matter a whit whether one adds or doesn't add the "On" -- everybody understands the sentence either way. So, why isn't DL accepting it either way? Its failure to do so, and this whole discussion, strike me as a classic case that Shakespeare would call "much ado about nothing".
Every language has its own way to express itself, so when Italians say : "Il lunedì non lavoro." ( translated ) "On MondayS I don't work" They don't need to say it in plural, I guess when they want to be specific, they can say : "Questo lunedì non lavoro." translation : "On Monday I don't work" or "This Monday I don't work". I hope this helps.
These boards are suppose to be safe places to discuss. I had read through a great deal of this discussion and still remained confused, thus I asked. I see you did a good job answering the question two months ago -- but clearly I did not wind my way down to your response. Perhaps that is why you are frustrated by people re-asking questions, but frankly I find I benefit by all but the most cynical of responses.