I agree. To a native speaker, it could easily be translated as "I'm not able to run today" or, even better, "I can't run today". These kind of mistakes make me think that a portuguese native speaker, with english as a second language, is the responsible for Duolingo' Portuguese (beta).
It is right, and your version too.
The notion of "stative" verb exists almost only in English. (Comparing only English and Portuguese)
These weird sentences in English would be perfectly fine in Portuguese:
- Estou podendo correr = I'm able to run (compared to "I'm being able to")
- Estou sabendo das notícias = I know about the news (compared to "I'm knowing")
- Estou gostando disso = I like that (compared to "I'm liking that")
In Portuguese, I had never heard of this concept, but after I got used to the English stative verbs, I could detect one in Portuguese (the only I could so far):
It's one of those that change meaning if you put it in the continous form:
- Eu conheço aquela menina = I know that girl
- Eu estou conhecendo aquela menina = I'm getting to know that girl
With "poder", they're the same.
Generally, it's pretty much the same difference between simple present and present continous in English for verbs that accept that.
Simple present: suited for general cases where a specific time (now) is not important. (In Portuguese, also good for continous actions, some verbs being more suited to this than others)
Present continous: suited for actions that are taking place right now.
With the verb "poder" they're pretty much the same, and the simple present sounds a little better in any case.
With other verbs, such as "saber", the difference is more clear:
- Eu não sei fazer isso = I don't know how to do that (a plain statement, general and timeless)
- Eu não estou sabendo fazer isso = (I've been trying, but) I don't know how to do that // I'm not able to figure out how to do that (since it's "continous", it suggests I'm trying and failing).
For those who wonder what's the Portuguese verb for this "can":
- Minha esposa está enlatando pêssegos e peras esta tarde
PS: who knows what was in my head two years ago...
But that sounded like a Brazilian expression "estar podendo" meaning something near "to be in a great state, capable of achieving many things" (this can apply to money, to beauty and some other things).
Yes. In PT, any "ndo" is called a "gerúndio".
Interestingly enough, most true English gerunds are not "ndo" at all in Portuguese, but infinitive verbs or some adaptation to adjective forms.
- I like being here = Eu gosto de estar aqui
- The sleeping bag = O saco de dormir
- The fighting warriors = Os guerreiros lutadores