What can teachers can't and can say in a clroom?

I am in the 7th grade and my teacher is teaching us the bill of rights, contitution and the judicial branch. Although shes teaching all of this she is imputting alot of her political views in it. I just want to know what teachers can and can't say in a clroom or while thier teaching. In your aswers would u provide me with some sites i can visit to help me with this question.