How to eat the second-level skill book in the free world?

The success rate of eating books directly is very low, and the lessons of our ancestors are high. I suggest eating books before the morning, one every other day, and it is best not to eat in the afternoon and evening. According to my experience of eating G directly, I can conclude that M 1 is 1 for M2, M2 to M3 is 2, and so on. Another secret was revealed. Suppose you are over 2M, 1M is unnecessary. Sometimes going to the mysterious old man's fortune-telling can predict the success rate of reading. For example, I suggest you not to eat expensive books (such as firm but gentle flame =)