"The postman is not a man."
Translation:A postás nem férfi.
"A postás nem ember" should be accepted, too, in the sense he is not human but extraterrestial or ogre.
A postásnő nem férfi is not accepted? Is this a mistake or on purpose? I would have thought that logically, by not being a man, the postman is a woman. (Or trans or something else, but this is a beginner's sentence).