Jak by bylo anglicky "Nemůžu vidět ty osly." ?
I cannot see those donkeys.
Alternativne, se da rict "I am not able to see those donkeys". Nejsem schopen ty osly videt. Mezi mnou a nimi je dům.
"Já ty osly nevidím" translates to "I don't see those donkeys", not "I cannot see those donkeys"
both are correct
and again why you say twice I "Ty Osly nevidim" should be enough isnt it?
What twice? There is only one Já. If you skip it, it remains implicit, that's all. But you absolutely do not have to skip it.
What are the other terms of osla or donkeys in czech and when do you use it? What are their meanings of it?
Please first check the Tips https://forum.duolingo.com/comment/25088573 I linked. Only then start asking all around the place.
what's the difference between "osly" and "osli"?
Osly is accusative plural; osli is nominative plural. You need here the accusative because "those donkeys" is a direct object.
How come it has to be in the order of Já ty osly nevidím, and it is wrong as Já ty nevidím osly?
You can't separate "ty" and "osly", that would be exactly like saying "I those cannot see donkeys." Otherwise, there are other possible word orders here, for example "Nevidím ty osly."