Extremely late response, but I'm going to share anyway to test my own recall. A rule of thumb I picked up was: whenever you're using a verb similar to "start" (i.e. comenzar or empezar) succeeded by another verb, then "a" is used to separate the two. For example, el jugador comienzo a jugar el partido. But when you're using a verb similar to "finish" (i.e. terminar) succeeded by another verb then "de" is used to separate the two. For example, la maestra termina de hablar conmigo.
Like AaronTovo said, to "finish" something implies that you no longer have a use for that same something. Finish carries with it a connotation of completion; either there is nothing more to do, or you simply feel like you are done with what it was you were doing. "Finished" is more like the English word "done" or the Spanish "terminar" in this sense. Example: If I stop eating dinner, it's probably to answer the door. If I finish eating dinner, it's probably because there's no more food on my plate :)
Eating isn't the problem in this sentence. Duo accepts "She finished eating" no problem. You just wouldn't use ended here in English.
Although, finished and ended have very similar meanings and are often interchangeable, this isn't the case here. You can say a thing has finished or ended, a movie for example, but you usually can't say that someone has ended doing something.
I'm not really good enough with English grammar to give a better explanation as to why, but here are links to the English dictionary entries for both words that might give you a better feel for their usage.
Yes, "she ended eating" is comprehensible, but it's not something we say in English. In hopes that it helps, "She finished eating," would be interpreted in English in the sense of this exercise-- she ate everything completely or until she wasn't hungry. In contrast to that, "She ended eating," would mean that she stopped the act of eating from happening ever again. Maybe she invented a food pill? ;)
Not a native speaker either, but "to stop to eat" would most certainly be interpreted as 'to stop in order to eat'. The idiomatic way of putting it is 'to stop eating'. "To stop to eat" therefore would translate to "ella se detenía para comer".
- to stop doing sth: aufhören, etwas zu tun
- to stop to do sth.: stehenbleiben, um etwas zu tun
The reason is probably that you only can stop an ongoing activity.
wataya is essentially correct. "She stopped eating," means that she was eating, but now she is not. In contrast, "She stopped to eat," means that while travelling from point A to point B, she stayed at a point C for the purpose of eating. The reason for this big difference is that typically we don't use the preposition "to" after "stop" as a pair. So the phrase "she stopped to eat" is not interpreted as "she stopped eating," but instead, "She stopped for the purpose of eating." This is a common English format [subject] [verb] [to + verb]--> The subject is doing something /for the purpose of/ something else. (e.g. "She drank to cool off" or "He killed to save his family").
The meaning is indeed close, but there is an important distinction to keep in mind. "Finished" used as a verb implies that the action /was just completed/. The phrase "is done" also means "finished," but it is more ambiguous about when the action stopped taking place. So, the difference between, "She is done eating," and, "She finished eating," is that perhaps she finished eating 30 minutes ago for the first, but she JUST NOW stopped eating for the second. Hope this helped :)