I believe the idea the Spanish sentence is conveying is that they finished off the food. If you ask someone if there are potatoes and they've been finished off they will say "se acabó". You can use this verb to mean finishing an action, such as "acabaron de comer", they finished eating, but in the Spanish sentence at hand because the food is mentioned I believe the focus is on that the food was finished off and not that they stopped eating.
Is "acabar" both "to finish" and "to finish up/off?" Or is there a reflexive form for the "to finish off/up?" version? Reading this sentence, I wasn't quite sure if it was "They are finishing the food." - as in finish preparing the food to be served - or "They are finishing up the food." - as in they are eating it all. Is there a way to separate the two ideas? Or is it strictly contextual? Thank you!
I see that your level on Duolingo is much higher than mine. But, it has been a year since your post and I'm wondering if you have learned more about "acabarse" since you posted this. I still am learning about it.
In my thinking, in English, there probably isn't a lot of difference between "they finished the food" and "they finished off the food" if it is said in the same context and sentence structure, I believe that adding the "se" as you have above makes the verb transitive and can then give more of the meaning of "finish off". On Spanishdict.com, they show an example with "se": se ha acabado la comida = there's no more food left. This leads me to believe that your phrase "se acabó" needs to be translated more like "It was finished off" (past tense), whereas the above sentence is not reflexive as evidenced by the fact that the subject is "they", not "it", and there is no "se" present.
I am also seeing that you need to add "con" after the verb to give this meaning when adding a noun like "la comida" after "acabar" (not acabarse). Example: Acabaron con la tarta = They finished off the cake.
On the other hand, Spanishdict.com gives a sentence where "acabar" comes after "para" and also means "finish off": me quedan solo un par de horas para acabar este cuadro = it'll only take me another couple of hours to finish off this painting. So, I'm not sure if the position after the "para" makes a difference or not.
I'd also like the answer to your questions, NEGenge: "eading this sentence, I wasn't quite sure if it was "They are finishing the food." - as in finish preparing the food to be served - or "They are finishing up the food." - as in they are eating it all. Is there a way to separate the two ideas? Or is it strictly contextual?"
Yes, but it's for a different meaning of "stop".
Here's a good discussion of parar/acabar: http://spanish.stackexchange.com/questions/1004/different-words-for-stop
If you're on Windows, enable the International Keyboard. http://symbolcodes.tlt.psu.edu/accents/codeint.html. Then you can get upside down ¡ and ¿ and ñ by adding the ALT key. And you can get accents by hitting ' then e etc. The tricky part is typing quotes, but you get used to typing a space after the quote to get the quote to appear.
Amartya, maybe this reference can help you somehow:
When I got Windows 10, I'm pretty sure I followed the instructions here. http://answers.microsoft.com/en-us/windows/forum/windows_10-start/us-international-keyboard-for-windows-10/f0dc89e9-2373-42af-bb2e-f50b8a69a13a
I put "They are going to finish the food" and got it wrong twice, when that's how it translated earlier in the lesson. After I put the answer Duo suggested, which is "They are going to finish up the food," it said, "Another translation: They are going to finish the food." That was my first answer! Gahhhh!