Translation:In a moment the boy finishes his dinner.
This isn't fair. We all know that the present tense can be used in Italian (and English) to refer to a future event. It makes more sense to translate, "in a moment he will finish dinner" and still remain faithful to the Italian. I have seen duolingo translate the present as a future in other exercises so I figured it would be allowed.
Hey, this is a free site. You get what you pay for. They're very inconsistent with allowing translations of Italian present tense verbs into future tense in English. So I default to using present tense translations while reaping the understanding that, in Italian, it appears to be okay to use present tense in the sense of "am/is/are going to..."
The English translation can be understood in either case that you state IGFS. Both are equally correct. Additionally, the Italian present tense is often used to express the near future. I'm not too sure how long that extends into the future but certainly long enough to either gobble up a meal or take a more leisurely approach. Hope this helps :)
Maybe I can help a bit, although I'm not Italian. In my language we sometimes use present tense even if we talk about the future, in order to "raise the tension" of the narrative. It is most commonly used in literature and in storytelling. From this point of view, the above sentence would be completely normal, as it should be understood according to siebold's interpretation. Of course it is hard to judge without a context, which is Duolingo's notorious flaw.
The English translation given above is a real stretch. That is not to say that one could never imagine a reason to say that, but in almost every case it would be a poor choice. Moment is usually not intended to be precise, so if I wanted to say he eats in a minute I would say something like "He finished his dinner in only one minute." In a moment is much more likely to be used to indicate the near, but indefinite future. "I will be ready in a moment." "In a moment (i.e., very soon) the boy will finish his dinner."