Translation:A calendar for the year two thousand and seven
"the calendar for 2007" not accepted. I saw this question and knew right away, there's no way to guess what the gnomes at Duolingo will accept. Other Duolingo courses are far better. Maybe we should just pay a few bucks to learn Swahili at Memrise or Babbel, and turn to the really excellent courses elsewhere on Duolingo..
Thanks for the tip about Memrise. It looks very promising. Is it free? https://www.memrise.com/courses/english/swahili/
It's true that Duolingo Swahili is way behind the other Duolingo courses. Duolingo German is great, but they must have massive resources in comparison - certainly masses of Beta testers before its release. See Vitoreiji's comment above and keep reporting, especially if you use the Android app and can specify exactly what the error is.
The -a of association literally translated is 'of', but an equally correct translation as clearly stated in the notes would be to place everything after the ya in front of the noun, calendar, as an adjective phrase? Would 'the year two thousand and seven calendar be wrong'?
I've reported this issue on several other exercises in this course, but the answer that is given here is wrong. English NEVER has the word "and" included in numbers. While it is a common mistake, it is not correct. It should be "Calendar of the year two thousand seven", though "Calendar for the year two thousand seven" or "Two thousand seven calendar" would both be more common ways of saying this. It gets frustrating enough trying to get an answer that Duolingo accepts for this course, but is even more so when it rejects a correct answer in favor of one that is wrong.
Actually, that's American English. In British English we do insert the "and". But still I agree with Garpike above: Writing out a year in full, although perfectly correct, is not usual practice in English. (I suppose it wouldn't be usual practice in Swahili either though, but one of them has to be written out to stop us being lazy.)