There are many questions here on duolingo to help someone learn a language, except some of them are not accepting of different forms. If you test out of a skill, duolingo will only accept words in that "chapter" and not other words that mean the same, but are different. This can be frustrating for people who already speak the language. I believe that duolingo should have more correct answers, that accept different word phrases.
When you provide a correct answer that Duo does not recognize as being correct, there is a button to report errors. Click it and check "My answer should be accepted" and the course builders will add your answer into the database of accepted answers.
Ah, did not know. Did not want to click on that button because although there is nothing wrong with the question, I just was annoyed that it happened. Thanks for telling me.
P.S. Writing stuff in the sentence comments does not help, because the course builders don't necessarily read the comments for the various sentences. They DO see the error reports though.