"It is eating an apple."
Translation:Es isst einen Apfel.
Maybe this will help more? http://fr.wikibooks.org/wiki/Grammaire_allemande#Les_d.C3.A9clinaisons
I thought it was fressen, but I know what you mean. I thought it was really odd to see the sentence as it is.
Because an apple is masculine, therefore you have to use einen. If it was feminine you would have to use eine.
When is it Ein and not Einen? There are problem before where it ended in "ein Mann" and it was correct that way.
I think it has something to do with the positioning of the words, but not sure.
ein- Neutrum (neuter) ie. ein Kind
also can be maennlich (masculine) ie. ein Mann
however, Mann can also be einen Mann (ie. Sie hat einen Mann) the difference: in the first case, Mann is in what Germans call the Nominativ, (the subject). In the second example, Mann is in the Akkusativ (an object). To show it is an object, German use einen instead of ein
eine- weiblich (feminine) ie. eine Frau The unfortunate part is you pretty much have to memorize these.
Usually, the context would usually clear it up. For example, if I asked "Was ist das?" (what is it), you would say "es ist Brot." Conversely, if I asked "Was isst es?" (what is it eating), you would say "es isst Brot."