"That building is brown."
Translation:Doq qachvetlh 'ej Qaj wuS rur.
It needs the rur -- but yes, it should be Doq 'ej Qaj wuS rur. See the comments on the reverse translation: https://forum.duolingo.com/comment/28682188
I've replaced the Klingon sentence now to Doq qachvetlh 'ej Qaj wuS rur, which thus becomes the preferred translation for this English sentence. Doq qachvetlh 'ej wovbe' is also accepted.
Doq 'ej Qaj wuS rur refers to a particular shade of brown, not to all the shades encompassed by the English word "brown".
I've "deleted" the other sentence, but the sentence discussion is still there and attached to that version of the sentence.
I created a new Klingon sentence which will have its own sentence discussion page as soon as someone posts a comment on it.
But since I used the same English translation, this discussion page will continue to be used for the reverse translation (Klingon-to-English) exercise.