Be beyond (one) idiom
If something is beyond you, you find it challenging to understand it or to carry it out.
Why did you ask me to fix the roof? It's beyond me.
I will never understand why my mother made me go to a military school for one whole year. It's just beyond me.
This piece of literature is beyond me. I don't like reading classic books.
It is difficult for someone (not) to do something.
Used to refer to something that is confusing, mysterious, complex or difficult to understand
The verb "be" should be conjugated according to its tense.