"An avenue is a very wide road."
Translation:Aleja to bardzo szeroka droga.
Aleja jest bardzo szeroką drogą.
"bardzo" as an adverb doesn't change, "szeroka droga" as a noun phrase goes into Instrumental.
Is this true of Poland? Here in Canada an avenue is a road that runs east to west and a street is a road that runs north to south
Really? I have never heard about anything like that o.O
Generally yes, 'aleja' is supposed to be wider, but sometimes it may just be a name without a real reason.
Jellei, you won't be surprised that I was surprised that Duo rejected "Aleja to bardzo szeroka ulica". (I wrote about road vs. street in another thread.)
To an Englishman living in Germany, Duo's English sentence is ... confusing. My definition would be: "An avenue is a road lined by trees" ("Eine Allee ist eine von Bäumen umrandete Straße"). There were many such main roads in East Germany (former GDR) before they were widened after German unification to improve traffic flow.
(1.1) droga wysadzana po obu stronach drzewami lub krzewami; zob. też aleja w Wikipedii (1.2) szeroka, reprezentacyjna ulica
So 1.1 is the same that you mean, but here we have 1.2.