"The Japanese child climbs up onto the car."
Translation:A japán gyerek felmászik az autóra.
Why is the version "...mászik fel az autóra." not correct?
Well, there are some typos in your sentence, so not correct at all :-)
"A japán gyerek az autóra felmászik."
...is a bit unusual but not wrong at all. The focus of the sentence is always in front of the verb, and in your case on the prefix: the child climbs UP on the car (and not DOWN for instance). And this is unusual, because it seems first, you want to focus on the car, but finally there is the prefix in the focus.
In a narratve sentence it is usual to take the subject on the first position followed by the verb with the prefix in the focus and finally the "object" (though "az autóra" is not an object from the hungarian point of view).
=> "A japán gyerek felmászik az autóra."
Focussing on the CAR: "A japán gyerek az autóra mászik fel"
Focussing on the CHILD: "A japán gyerek mászik fel az autóra. / Az autóra a japán gyerek mászik fel."
But without any context at all Duolingo has to accept all the grammatically correct versions. And this is one of the big problems, that exists since this course was started, already before its Beta-Phase :-)
Thank you for the explanation and the last paragraph. As far as the typos are concerned, I agree that I sometimes make spelling mistakes in the discussion, however, there were no mistakes in the exercise. I realize when an answer is rejected because of a spelling mistake and my comments only concern the grammatical aspects.In addition, since I have no hungarian keyboard and cannot use the alt+ key combination, there are some letters that I cannot write in the discussion.
The word order issues in this course are really annoying - the rules about the topic and focus are nicely and clearly explained, but without a context it is almost impossible to figure out what is supposed to be a focus in the english sentence, which renders the choice of a correct hungarian word order almost impossible.
Or am I missing something?
You are absolutely right. That's one of those quality issues of that course since it exists.
One of the contributers himself explained, the longer the sentences become, the more difficult it becomes to enter in the database all the possible sentences in hungarian. So I asked him, if the contributors know about this problem, why are so many sentences in that course so long? Until today I have got no answer. Maybe there are too many ways to answer ;-)