This is my question, which was closed because I was asking 2 questions in 1 question... but now I removed the first question and made it focus one question only. So why is it not re opened now?
So I was the one that closed the question. Your edit has placed the question into the reopen queue.
As a moderator, I could (like I did for close) unilaterally reopen the question, but there are (in my opinion) still problems with it. Regardless of my opinion, the question is in the reopen queue. As qualified community members take the time to look into the queue, they will vote to reopen or not as they see fit. This can take some time, please be patient.
As to my opinion of the continuing problems of the question:
Please be aware that the expressed point of the Stack Exchange network is not to answer your question, but to create a body of questions and answers that are hopefully helpful to many people, not just you.
The question still seems to ask multiple questions, but stops at 1. Very confusing:
Just to get a better understanding of how does bert work.... I wanted to know:
It feels like a homework problem
This feels like a homework problem that you would like an immediate answer to, so that you can get a grade instead of taking the opportunity to learn.
These sorts of questions are often poorly received here.
You have posted it to multiple Stacks
In general cross posted questions are poorly received.