"The professor eats with the chairman."
Translation:Der Professor isst mit dem Vorsitzenden.
I see that it's been highlighted that chairman is singular and when you get the translation wrong, the answer tells you it should have been plural. I'm guessing that's a bug as if it was plural, it would be "isst mit den Vorsitzenden"
I'm basing this on the fact that Vorsitzende is one of these special nouns that take a "-n" in dative. Is there any method to identify these nouns?