Translation:The black dog lies down on the carpet, not the bed.
Well, in English (at least the way I speak it), you can't "lie onto something" -- "lying" is the state of being horizontal, and a movement which ends up in a horizontal state is "lying down".
So the "down" in the English sentence comes from the fact that movement to a lying position is involved (the movement is implied by the directional suffix -ra rather than, say, -n for "lies on the carpet").
Similarly with "sit" (state) versus "sit down" (movement to sitting position) or "stand" (state) versus "stand up" (movement to standing position) or "go and stand" (ditto).
Well - I would have answered that the carpet not necessarily lies on the floor (also it is to be assumed ;) . So the -ra suffix not always includes the meaning of something that is under your current position. It can be everywhere.
For me the given sentence does not necessarily include a movement. And the answer 'the dog lies ON the carpet' (without movement to there) does not feel wrong to me...
If the rug is on the wall the dog cannot lie on it. So as the dog is moving to lie on the rug, the simplest way in English is to say "the dog lies down on the rug".
If it was "the dog lies on the carpet" ie no movement aka "the dog is lying on the carpet", it would be "a kutya a szőnyegen fekszik".
Thanks a lot! You were of course right with that. The 'en' suffix was a point that I did not think of, when I wrote my answer.
And the other point was, that the carpet may lie on a platform or something similar that might be a little higher than the ground where I am standing. So the 'ra' ending does not necessarily include the "down" meaning here. But in this context and when excluding my wrong thoughts (that he is 'only' unmovingly lying there), it seems right ;-)
So sorry again if I confused someone.
Thanks, I understand what the Hungarian sentence implies, I just asked why it isn't matched with the English translation. I think the app should be a bit more lenient, and not insist so much at the nuances in the English language, and focus instead on learning Hungarian (which in this case means accept when we translate something into English exactly the way it says in Hungarian (without "le"). Sometimes I feel like I'm doing an English course here...
why it isn't matched with the English translation
Word for word translations don't work well with Hungarian.
While you can use "lies" to imply movement in English, the only way you can tell that the student knows that if to insist on "lies down". Better safe than sorry :-)