It was like this at first. Everyone's foundation and strength are different and cannot be compared. When reviewing for the postgraduate entrance examination, we must grasp the foundation. We can read the math textbook first and do the after-class questions to find the feeling. Finally, some formulas are derived, which are absolutely easy to use and increase understanding. It's okay to slow down at first. If you lay a good foundation, you will have no problem. Postgraduate entrance examination is the foundation. It was much better after one time. Follow your heart.