This is a normal phenomenon, because sometimes you just look with your eyes, and knowledge like science is not what you look at and recite, but what you do. Scientific knowledge is flexible to manufacture and apply, not visible. Of course, you can't say that you don't need to read it, but you must read it, just as scientific concepts must be memorized. If the concept is unclear or even unknown, it is even more difficult to do the problem. Therefore, books should also be read frequently.

However, you should always practice over and over again. Don't think that you don't have to do it if you do it. This is a wrong idea. Have a less troublesome mentality and attitude.

Let's go Work hard.