Okay, kiddo, let me try and explain Poland A and Poland B to you!
First, imagine you have a big chocolate bar that you want to share with your friends. But, instead of giving everyone an equal piece, you decide to split the bar into two parts - one part is bigger than the other.
This is kind of what happened to Poland during World War II. After the war ended, the country was split into two parts - Poland A and Poland B. Poland A was the bigger part and it was controlled by the Soviet Union, while Poland B was the smaller part and it was controlled by Germany.
The borders between Poland A and Poland B were really important because they determined which country had control over different parts of Poland. And, as you might imagine, this caused a lot of tension between the Soviet Union and Germany.
But eventually, Poland A and Poland B were reunited under one government and the borders between them disappeared. Now, Poland is one country and its government is independent and democratic.
So, that's Poland A and Poland B in a nutshell. Of course, there's a lot more to this story, but I hope that helps you understand the basics!