basic indefinite articles

Question

Why would I use an indefinite article with some nouns and not others?

Example: "Come sandi`a." vs. "Come una naranja."

Answer 1

Someone asked this question before, and I thought this answer might help you out.

when-to-use-indefinite-articles

Hi Katie, I modified your link to give direct access. - Eddy, Jun 15, 2012

Answer 2

I would attribute it to the fact that you ate an orange but you did not eat an entire watermelon, just some of the watermelon. I know watermelon is good but typically is not eaten by one person in one sitting. The orange, on the other hand, is usually eaten by one person in one sitting. (At least, that is what is implied.)