In my impression, such people are deeply hidden in school and study. Usually I don't feel how good I study, but when I get to the exam, I seem to fail and my grades are among the best. If the score is too high, you will find it unreasonable, because he is ordinary to you at ordinary times, but in fact he belongs to the hidden type, full of knowledge and doesn't want to show it. So we can't just look at the appearance at ordinary times, and the appearance can't represent anything.
When I was in high school, there was a buddy in my class who was not so strong at seeing and studying at ordinary times. When he was in senior three, his life seemed to be dead. He jumped to the top of the class, and every time he scored a new record in the exam, the whole class was dumbfounded. I can't believe it's true. Because when he was a freshman and a sophomore, he talked with many classmates in class. After class, he either sleeps or cut class goes to the Internet cafe. However, everyone has one characteristic: teachers teach well, and their grades are not too bad or too good. But after the third year of high school, people began to study hard, didn't sleep after class, didn't skip class and didn't surf the Internet. Study hard every day and your grades will soar. We all call such a person a dark horse, a master of hiding everything.