"Our blood is blue, not red."
Translation:Darah kami biru, bukan merah.
I'm confused about why this is "bukan" rather than "tidak", since "merah" is an adjective
sorry for late reply, but basically it is wrong. The course does have some errors. Assuming my Indonesian teachers at my school are correct (I am doing duo lingo onto of school to help with yr 12).
It should be "tidak" as "bukan" is the word "not" exclusively when comparing two nouns. eg, "pena, bukan pensil", whereas tidak can mean "not" any literally any other circumstance, "warnanya tidak merah", "saya tidak suka wajah saya", "kamu tidak gemuk", dll.