"A man and a woman dance."
Translation:Viro kaj virino dancas.
Because it's more simple like that. There are many real languages without articles at all.
Because "la" means "the". The translation doesn't ask for a definite article.
I studied French for many years and I sometimes have that problem with Esperanto too :)
"La viro" would mean "the man". La is a definite article. Esperanto doesn't have a word for indefinite articles, so instead of saying "a man" like in English, you just say "viro".