More Useful Feedback
Are there plans to provide better explanations for incorrect answers than is currently provided? Now they're mostly useless and harmless or incorrect which is detrimental to a student's learning. For example:
Correct solution: We have not seen each other since Wednesday.
You need the article "each" here.
First of all, ''each'' is not an article. It's an adjective. Secondly I don't understand why ''nos'' is translated as ''each''(''nos is also not an article btw) although I suspect it has something to do with the subjunctive....which I haven't even reach in the course yet. I find that, along with memorizing words, I'm just memorizing sentences which is not conducive to achieving some level of grammar and sentence construction mastery.
I'm finding that quite a few of the explanations don't make any sense at all, are incorrect or there simply is no explanation so the student has difficulty self helping. I'm in the Spanish verb particple section and I'm pretty sure this error has nothing to do with v. parts.
Hi there, good looking out for that feedback message! "each" is in fact a determiner (http://en.wikipedia.org/wiki/Determiner), which is the linguistic class that articles like "the" and "a" belong to, as well. That's why our error classification system jumped to the conclusion that you had left out an article. However, you are absolutely right in that the message is not very helpful. I will make sure that you (or anyone else, for that matter) will not be shown the message again unless you have actually left out a "real" article. :)
Now to your question about "nos": In the sentence "No nos hemos visto desde el miércoles.", you should have seen a little hover window saying that "nos hemos visto" should be translated as "(we) have seen (each other)". We show you these hints when it is not a good idea to translate word for word. As a simple example, take the expression "I am hungry". In German, that's "Ich habe Hunger". Literally, that means "I have hunger" - though that is not really a good translation, right? For questions like where the translation of "nos" came from, the sentence discussion thread is usually a good place to start.
In general, please keep the feedback coming when you see an explanation for a mistake that does not seem to make sense. We're working very hard to avoid that and to provide specific feedback messages for more and more types of mistakes. :)