You mean your instructor gave you only one hour's notice for taking the exam ??? I never heard of such short notice exams except possibly pop quizes, and with those you are expected to have already studied the material.
hiOur teacher has a weak knowledge about his subject
If your teacher were weak at that subject, why would he teach you in that subject? Moreover, haven't you already learned about those kind of things? I'm sure that all the items that appear on the exam are what you've already learned.