Because the USSR and Germany wanted to delimit between themselves spheres of influence in central Europe. Thus, the territory of Poland was divided between them even before the start of the war. In fact, the USSR acted for its own interests, like Germany, then no one could imagine that they would fight against each other.
One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.