Problem with Genitive case sentence
Das ist das Haus der Großeltern should be translated as "This [or that] is the grandparents' house." Note the apostrophe after "grandparents", required in English to make the word possessive. Duo counts the translation as correct, but says the apostrophe is a typo.
Obviously, this needs to be corrected. But there is no way to report the error. The only error-reporting possibilities are that the audio is wrong, the dictionary hints are wrong, or the German sentence is unnatural.
As @domlecon pointed out in the discussion for that item, a language-learning site really needs to teach correct grammar, especially on an item like apostrophe use that so many native English speakers screw up.
Please, send a bug report via
Grandparents is the plural noun of grandparent. Grandparents' is the possessive form of the of the plural noun grandparents. For example:
My grandparents have a nice house. I enjoy staying at my grandparents' house.
In my opinion, you are correct and Duolingo should have accepted the apostrophe without complaint.
Yeah, this does make sense. Even though some people here speak English and want to learn a new language, the website should not be saying things to us that are incorrect grammar in English, because we could be learning a tiny bit of bad information and we might not know it (NO OFFENSE WHATSOEVER TO DUOLINGO!!!!!!).