Translation:There are many rooms in the new American houses.
uhhhhhh there's clearly "az" at the beginning of this sentence, so why doesn't "There are many rooms in THE new American houses" work? Does Hungarian work like French where definite articles are needed for generalizations?
From what I have learned in the course, yes, definite articles are needed for generalisations in Hungarian. (I think this was also mentioned in one of the lesson notes somewhere.)
But the "the" interpretation should also be possible and accepted, I think.
Hungarian uses van in "to have" constructions, but van doesn't mean "to have". Those constructions are pretty specific with "[Owner]-nak van [possession]-ja" ("For the owner there exists their possession") and you neither have a -nak suffix nor a possessive marker in this sentence.
Then again, I probably should be more liberal with my assessment of translations. Hungarian doesn't have a word to the ubiquitous "to have", but just because of that I shouldn't disregard valid translations. So feel free to decide for yourself. :´)
"The new American houses have many rooms in them." Marked incorrect. Where did I go wrong?
It's a reasonable translation and it should be accepted. It's just not super straightforward. The Hungarian sentence uses van, which usually translates to "there is" in these kinds of contexts.