then a significant English translation should be something like 'My father has [present] many previous experiences'… Which is at least clumsy English and should be phrased as RickBradford suggested.
You're not translating the message, but a mix between 'grammatical' structures, which you deem equivalent between Greek and English, and meaning, imho
It's true, the English phrase is clumsy, if not completely wrong. From your comment it was not very clear what your point was and I assumed you where looking for the nearest Greek translation for the English phrases in it. :)
Edit: I wrote 'your comment', meaning garpike's comment, sorry.
Thank you. I asked because the hints for 'εμπειρίες' give both experience and experiences; in English 'experience' can be both countable and uncountable, and I wasn't sure if this was suggesting that the uncountable sense would be expressed in Greek using the plural form.
'My father has many experiences' means he is having them right now (unless we're in the historic present); it is not easy to think of a scenario in which one might say this ('The séance is in progress and my father has many experiences', perhaps). Unless this sentence really means this in Greek too, there is clearly a tense issue that's not being translated properly.
Like M., I'm wondering if this plural formulation (especially in the present tense) sounds any more natural in Greek than it does in English. In my reading, I've encountered many instances where "... έχει πολλή/μεγάλη εμπειρία/πείρα" was used. Outside of Duolingo, I haven't run into either "... έχει πολλές εμπειρίες" (in the present tense) OR "My dad has many experiences."
My father is very experienced = Ο πατέρας μου είναι πολύ έμπειρος. This uses an adjective, replaces very with many and is with has. In short, it's a different sentence. While more natural (although I'd argue My father has had many experiences is not too bad, with that tense), this is not how Duolingo works. Duolingo favours direct translations as it grades your understanding of translating individual words, unless it's a fixed expression.
Another note on how Duolingo works: forum moderators cannot make any changes to the lessons, only course contributors can. The way to reach them is by filing a REPORT, using the report button. :)