past participle of word have and become

I am being asked to give past participle of each verb , these being , Become and the word Have , I am totally at a loss , it seems is many contradictions as to answer and i am even wondering if the school is correct ? as from my learning and also research it points in that direction , past participle of have is have , even tried that and get told wrong , same with become , have gone over and over , is also some other tasks that seems or appears school is wrong about , when i look around the world it appears many grammarians all have different points of view and can see is many interpretations being applied , how do they expect us to pass exams if even there own teaching is contradictory