"Although the weather is bad, the children are playing outside the house."
Translation:Kvankam la vetero estas malbona, la infanoj ludas ekster la domo.
I translated this as Malgraux la vetero malbonas, la geknaboj ludas ekster la domo. It flagged Malgraux as incorrect. I tend to use malgraux and kvankam interchangeably and almost always use Malgraux in as kvankam just sounds rather odd to me. It seems to me to be a functional equivalent. It is expressing the idea that not withstanding the tornado down the street, the kids are enjoying themselves in the back yard as long as they can....
Just a side note for one who knows more than I about Esperanto. Is malgraux the opposite of graux, and if so what does graux mean?
According to Lernu's vortaro, "malgraŭ" is not a compound word; it doesn't mean the opposite of "graŭ" despite looking like it. In fact, it seems that "graŭ" isn't a word at all.
malgraŭ most probably comes from french "malgré" in which mal actually indicates the opposition with gré [Latin grātum, from grātus (“agreeable”)] which means will, liking, satisfaction, pleasure. So malgré means against my (or somebody's) will, liking, satisfaction, pleasure.
I know you can say "Kvankam la vetero estas malbona, la infanoj ludas ekster la domo."
But what's wrong about "Kvankam la vetero estas malbona, la infanoj estas ludas ekster la domo."
I'm sorry if the answer is obvious. I think there must be something about the use of "estas" that I just don't understand yet. There's something I'm assuming from english, I guess.
It looks like your sentence comes by analogy with the present progressive tense in English: "I am playing". In this example, notice how only "am" is in the present tense, while "playing" is a present participle (the form that ends in -ing). As far as I know, in either Esperanto or English, only the first verb should ever be in the present tense, which is why "estas ludas" is incorrect.
However, Esperanto does have a similar tense, which is formed with "estas ___anta"; in this case "la infanoj estas ludanta". However, it seems to be rarely used, according to the discussion at https://www.duolingo.com/comment/19810506/Present-progressive-in-Esperanto
I'm trying to understand why it's ekster and not ekstere. Isn't it working like an adverb here?