"There are trees, rivers and cities by the tall mountain."
Translation:A magas hegynél fák, folyók és városok vannak.
"Fák, folyók és városok a magas hegynél vannak" was wrong for me. I am having some trouble finding out the order of things in phrases like this one.
I understand words change order depending on the emphasis you wish to give, but when can I know a phrase is wrong, grammatically?
P.S.: The two correct solutions to me were: • Fák, folyók és városok vannak a magas hegynél. • A magas hegynél fák, folyók és városok vannak.
None of those sentences are grammatically wrong, but your first sentence means something a bit different, and it is slightly unusual. Yes, the position changes the emphasis. In that first sentence, you placed "a magas hegynél" in front of the verb, thereby putting the emphasis on it. To make it clearer what it means, sometimes it helps if we write the question that it could answer. Here it is:
"Where are there trees, rivers and cities?"
There are parts of a sentence that cannot be separated. For example, you wouldn't separate a noun and its adjective, right? So, "a magas hegy" needs to stay together. Other than these kind of restrictions, you can pretty much freely reshuffle the parts of a sentence. The result may have a different meaning but grammatically it should be valid.