"It is a dog."
Translation:Αυτός είναι ένας σκύλος.
why is "αυτός είναι σκύλος" not correct? Sentences like "είναι καθηγητής" (he is a professor) and "έγινε καθηγητής" (he became a professor) are ok!
I used σκύλος but it corrected me to σκύλι. Is there a prefference when speaking about a dog to speaking about the dog species?
It doesn't accept είναι ένας σκύλος αύτος which has the same meaning albeit different emphasis.
There's this phrase, "(Αυτός/Αυτή) είναι σκύλος", but it's way too colloquial and may convey different meanings depending on the situation. It's often used in cases of hard-working people or people who manage to pull off demanding tasks. However, it really isn't the most elegant of phrases and, for that reason, it's better to leave it out of the list.
But, anyway, info aside, your suggestion means "He is a dog".
I did write ένασ, not ένας. It's an error or - perhaps - a keyboard lapse ?