You can decide your grades without taking an exam once every three years. Besides, teachers should listen carefully in class. Remember the last lesson quickly after class. English accumulates vocabulary by reading more books, and mathematics by doing more problems. Think through the difficult questions first, you won't understand them without looking at the answers. Chinese depends on reading good words and sentences, copying them down and using them when writing. Biology, history and geography should be read, recited and practiced more. Although I am not a schoolmaster, I understand the premise of being a schoolmaster! Also, you should take your time and don't be arrogant.