In the past, the reputation was slightly lower than that of David Lee, but the arrangement was clearer than that of David Lee. Li Er's book is really good. It was used in all three exams, but it has not been published yet.

In fact, it's almost the same as any one. As long as you master any one, it's no problem!

The first set of exercises used to review in the basic stage is "660 questions of basic mathematics", which is very useful for laying a solid foundation and deepening the understanding of concepts. It is recommended not to do it too late. It is best to review the whole book once, which can not only test the effect of one round of review, but also guide the second round of review.