"Nem fehér madarak repülnek a tetőre, hanem feketék."

Translation: It is not white birds that fly onto the roof, but black ones.

[StevenMans2]

To clarify my report:

"Not white birds" in English is not very natural sounding. In English we would say "White birds are not flying onto the roof, but black ones."

Yes, I understand that to a non-native-English-speaker, this implies that this would be a translation for "Fehér madarok nem repülnek a tetőre", and you are not wrong. The secondary clause is what clarifies this in English, defining the "not" - the nature of the birds, or their act itself. Examples:

White birds are not flying onto the roof. (By itself)

White birds are not flying onto the roof, but onto the fence.
(Fehér madarak nem a tetőre repülnek, hanem a kerítésre)

White birds are not flying onto the roof, but jumping.
(Fehér madarok nem repülnek a tetőre, hanem ugranak)

In English, we differentiate them by word emphasis (executed similarly to how a Hungarian asks a question)

White birds are not flying onto the ROOF, but onto the fence.

White birds are not FLYING onto the roof, but jumping.

WHITE birds are not flying onto the roof, but black ones.

[_paranoia_]

But I think it should be "It's not white birds that are flying onto the roof, but black ones." (If I understand the meaning of the sentence correctly.)

[StevenMans2]

Sure, if you add "it's" to the first clause, it does also work, but so far that version is not accepted.

[_paranoia_]

Yes, not accepted, but I think this is the best translation of the sentence, as I understand it. Report!

[JMaxGlobal]

You write: "White birds are not flying onto the roof, but jumping. (Fehér madarok nem repül a tetőre, hanem ugranak)."

I believe what you mean to say here is that, "Fehér madaraok nem REPÜLNEK a tetőre..." (and not "repül" - as we are speaking about plural birds.)

[StevenMans2]

The sentence was placed as an example of structure, not as a translation of the original answer. But I do recognize the typo.

[kibla2]

And how about when you just WRITE the sentence: "White birds are not flying onto the roof." (and you want to emphasize: the birds are not white...)

[BigWayne19]

white birds don't fly onto the roof, but black ones do - duo is unhappy with this . how about : it's not white birds that fly onto the roof, but black ones ? . . .

[Mike943391]

Cant this be translated as No white birds fly..... ?

[StevenMans2]

Don't see why not.

[HeydenP]

And what about this: not white but black birds fly onto the roof . Is this wrong?

[StevenMans2]

Again, as noted above, it really doesn't sound natural in English.

[AngeElizebeth]

I had "it is black birds that fly on to the roof, not white ones"

so obviously wrong by duolingo standards.... I feel like my English and my Hungarian will both improve! :) Two for the "price" of one!