No, it has nothing to do with "the fact that factories originally were powered by water-wheels". :)
In the Slavic languges there is a verb from Proto-Slavic language: *vodìti 'to lead' (води́ть 'to lead, to conduct, to guide').
There are words from it like e.g. Macedonian водник 'a sergeant', Russian вождь 'a chief, leader, captain', Croatian vȍđa 'a leader, guide' or Polish wojewoda 'a voivode'.
It's a cognate to English to wed; the other cognates.
The factories in the times of "water-wheels" took people willing to work (without education or experience) [the Journeyman] and put them at one place where somebody would lead them [the Master craftsman] to do the work (this is why in Polish zawód means 'a profession' lit. 'after a guide/guidship; under the leadership' - 'a work learned with the help of a guide'); while somebody would set up the place first (this is why in Russian they have заводи́ть 'to start, to establish').
According to a moderator in another discussion, a завод is typically larger, more industrialized complex, for example transforming raw materials into useful industrial products for further processing (maybe at some other фабрики).
I gather that a nuclear plant, or a huge plant which transforms trees into standard-sized wood planks, would both be a завод. But a not so big suburban factory where such planks are assembled into tables would be a фабрика.
So it seems to be mainly a matter of "size", and the line between фабрика and завод is not perfectly clear. I hope that some native speaker comes by and validates that my previous examples get it right as far as "size" of завод and фабрика is concerned.
I don't think Russian makes a/the distinction between them, so when 'the' is required it should come from the English grammar. For me, it feels a bit difficult/like a line drawn on water, so maybe I'm not the best person to write about it, but here something.
So, it depends on the sentence - if it is obvious that we are speaking about a certain, well-defined group of workers (for example, in a defined factory), then I would speak about "the workers". Leave out the article ("workers" when you would use "a" when speaking about a single worker: if it's about workers in general, or when some workers are mentioned for the first time (in a longer text).
In Duolingo, if the sentence doesn't have clues or if it can be interpreted in both ways, I would simply assume that both should be accepted and maybe try reporting them if they're not.
I wish that Duolingo fully accepted English spellings and not underline them suggesting an error/typo. As we have been using them for centuries./typo American English is to my mind a pale alternative , so I shall continue to type 'labourer' not laborer. I will also use colour, glamour, armour etc too
Wouldn't it be more correct to use "в" instead of "на", since you wouldn't be working at the factory, you're working in a factory. I remember reading that "в" is used when the location is enclosed and "на" is used when the location is open. For example:
- Я бегаю на парке.
- Я работаю в магазине.
Please let me know if I'm mistaken in any way. I could also see "на" being used when your refering to the location that something is usually done in, which in this case would be working. I'm just not sure.
Realizing that prepositions tend not to translate consistently from one language to another, I was under the impression that на was on and that в was in.
Яблоко на столе. = The apple is on the table.
Яблоко в сумке. = The apple is in the bag.
Of course, that's a distinction between "on" and "in" and this sentence has "at."
Is "at" usually на or are there cases where it's в?
Generally it's true that в and на roughly map to "in" and "on", but I've found that it's better to just memorize what preposition goes with a particular noun. For example in the case of "at" there is:
Dad is at work: Папа на работе
Anna is at school: Анна в школе
It can be either В or НА depending on the noun.