"My mother brings us a cup of tea."
Translation:Moja mama przynosi nam kubek herbaty.
I don't get something either, because the only sentence that I could find was "My mother brings us a mug of tea." and this discussion is under "a cup of tea" (much more idiomatic, but not exactly the direct translation).
I will change "My mother" to "My mom", which is a better rendering of "Moja mama". But I don't know if this isn't some kind of a ghost sentence... I though that so-called ghost sentences were a result of our lack of knowledge about Incubator, but "My mother brings us a cup of tea." really doesn't seem to exist anywhere anymore.