I wrote "the boy eats the apple" and got it right. Can I assume the article "a/an" and "the" are indistinguishable in Polish? Also, are "eats" and "is eating" interchangeable in Polish? (forgive me for now knowing the syntactical/grammatical term)
Indeed, however, "the boy" can also be translated as "ten/tamten chłopiec (suggests a child)/chłopak", the same way that "the boy" can also mean "this/that boy" (which would be the direct translation of "ten/tamten chłopiec)
I eat - jem you eat - jesz he/she/it eats - je we eat - jemy you eat - jecie they eat - jedzą
Just because there are no articles in Polish, doesn't mean you can omit them in English translations in places where there should be one. Duolingo should let you pick any articles that are gramatically correct.
This looks sort of like Russian.
Мальчик есть яблоко (mal'chik yest' yabloko)
Also, chłopiec comes from chłop (man/peasant) and -iec (male). How you get "boy" from that I don't know.
Possibly because aristocrats considered themselves as one level above peasants, and considered them therefore as "boys"?
Not at all. The closest thing I can compare it to without using IPA is probably "hwoh".
If you are on PC, you can read the tips sections for every lesson. There should be an explanation in one of the earlier ones.
It should have worked, it's accepted. Well, it would show a message about a missing space or something ("A boy is" is accepted, I had to add the version with the apostrophe now), but it should have been accepted.