"Hello, thank you!"
Translation:Dobrý den, děkuji!
Yes, but when using the tiles (as was presented to me this last time), Ahoj was not an option. And since Dobrý den does not mean hello, I did not see a way of putting the correct translation without going to keyboard mode. It just seemed strange that this would be translated this way.
Both are correct. It depends on whom you are speaking to. Friends and family - ahoj, other people - dobrý den.
You can use it almost any time. "Dobré ráno" only for the first meeting early in the morning and in the evening when it is dark "Dobrý večer" might be better.
This is no clear-cut thing. But in this exercise we only consider universal greetings similar to Hello. Those ones that are not tied to a specific part of the day. So we do not accept any of: Dobré ráno, dobré dopoledne, dobré odpoledne, dobrý večer. We do accept Dobrý den, because that can be used at any time.
(I may have brought this up in the past...) My parents were both from Praha, leaving CSSR in 1945. I grew up hearing "Nazdar" - both as a hello and as goodbye (also S'bohem for goodbye - but I'll save that for another comment). "Ahoj" we learned in 1968 when the Iron Curtain was loosened and we visited the Mother Land. I get it that languages are living things, so I get it that "nazdar" is archaic. But is it used by native Czechs at all anymore?
"Nazdar" is not archaic, just two notches below "Hello" to serve as the main translation. We do recognize it in side translations.
Fwiw, your parents did not leave ČSSR in 1945. The official long name (almost without interruption from 1920) until 1960 was "Československá republika", so just ČSR. The other "S" did make an appearance by the time of their return visit. The name stayed like that for a few decades, and went through a few death-bed gyrations in the final years of that country, may it RIP.