English Definite Articles
I am very worried about the English Definite Articles in the course. We get many sentences like "The cucumbers are vegetables" Is this trying to say "Cucumbers are vegetables" ? These are different to each other.
The sentence in English with the definite article talks about a known group of cucumbers, not about cucumbers in general. The sentence without "the" talks about cucumbers in general.
So the English sentence is strange (even by Duolingo standards)
If you talk about cucumbers in general in Romanian do you use the definite article? I am guessing you do.
Yes. In Romanian, talking about things in general uses the definite article.
"Cucumbers are selling well for export." -- "Castraveţii se vând bine la export."
"Oranges do not grow in Romania." -- "Portocalele nu cresc in România."
"Water melons are very sweet over here." -- "Pepenii sunt foarte dulci aici."
Note: this is not an isolated case. French and Spanish also use the definite article when they talk about general truths.
It depends on the context. If you're referring to your example about cucumbers being vegetables in general, I agree that the English sentence shouldn't have the definite article.
In general, if you think you see a mistake, report it. The course is still in beta afterall.