Translation:Some sad events happened in the last years.
Strangely, this version is not accepted.
In the last years some sad events happened
Many variants are missing throughout the later stages of the tree, but not, usually, something as routine as this one.
I realize nothing is being updated in Turkish at the moment but perhaps in the future this language will be actively maintained, and the final stages of the tree finished.
Sometimes Duolingo seems to insist on a passive voice in the English version and sometimes it opts for what is more 'natural' English. Well, in English we are actually told to avoid the passive voice is possible. In any case, I think both versions ought to be accepted. As in this case, "In the last years [which perhaps is more natural as "in recent years"] some sad events were experienced/lived."