Yes, We are, etc. were already in the system, but there was another problem with the end of that accepted sentence... We fixed that now.
So I was going to write that you'll be getting an email about your report being accepted (if you have chosen that in your settings) in a couple of weeks, but the newest report of "We are" was from 1 month ago :-O
I have no definite knowledge, but from another course I have noticed, that if the misspelt word makes another word, it is considered an error (like writing "mouse" when you should have written "house"). If it doesn't make, it is flagged a typo (like writing "thr" instead of "the").
Omitting an article is another case. Since there is no word to compare against (the system compares " " against "the"), this seems to be flagged as an error.
I've already wished a setting for another course: "I'm not native English speaker and/or I'm not here to learn English, so just give me only a warning about article errors in English".
To add what Annika said…
For a subject to be in the partitive there are two requirements.
- the clause is so called existential clauses (something is somewhere)
Yes, Juusto on loppunut/lopussa (note, loppu is an erroneous sveticism; yes, I have reported this) is this kind, but…
2. a) the subject is an indefinite part of something
as it would be in Pöydällä on juustoa : There is cheese on the table
b) the clause contains a negation
as in Pöydällä ei ole juustoa : There isn't any cheese on the table
However here we speak about what has happened to a specific piece of cheese, so it's neither indefinite nor a negation. Therefore the subject can't be in the partitive.
I'm not good with articles in English (they are confusing to me), but IIUC the definite article shows this (at least in this case).
note, loppu is an erroneous sveticism
Yeah, I think you've lost that particular battle: https://en.wiktionary.org/wiki/loppu, for example :-)
It's like me and "alkaa satamaan" -- I know it's officially considered correct nowadays, but I will never say it and just hearing it grates on my ears.