I think perhaps workman should be an alternative to worker as a translation of εργάτης
I agree. Paper and online dictionaries all give 'worker, workman, labourer' which are in any case closely related in meaning.
"Ένας" is not mandatory. "Ο θείος μου είναι εργάτης." is also a correct translation and one of those shown in the incubator.
However, to complete the reply, "Ο θείος μου είναι ένας εργάτης." doesn't mean your uncle is plural but that he is "one of the workers".
I'm guessing this is "worker" in a more specific sort of understanding, like of the manual labor variety, rather than simply "one who works in some way."
yes, that 's correct, "laborer" is in the hints and I've added "labourer".
I'm not so sure of that but I am sure that your kind words are very much appreciated. I'll try to live up to them. Ευχαριστώ.
Note the word is "employee" with two 'ees" υπάλληλος this could be masculine ο υπάλληλος ot η υπάλληλος feminine.
Here's a set of good dictionaries. https://www.lexilogos.com/english/greek_dictionary.htm
Enas... Why is this used here correctly but not for the expression "my sister is a lawyer?". I used "enas" for the latter and was marked wrong, so i omitted it here and was likewise marked wrong.
It's more natural to omit "ένας". In fact, that's what you'd get to hear (almost exclusively). The thing is that the article has been included in some of the possible translations to better match the English article "a" so that it's easier for learners to match the two words. However, this leads to a more unnatural sentence. Not in all exercises have the two versions (with and without the article) been included, so there are a few inconsistencies throughout the course. We've started omitting it in the second tree. In this exercise, however, both should be accepted.
I think it would be different anyway for the sister -> Η αδελφή μου είναι μία δικηγόρος - a lot of occupations don't have a feminine equivalent, so just use the masculine form - but with feminine articles IF needed. Better without in this case!