Thanks to the tips and support of friends, the selling price of the old books in the previous chapter is all true, not made up by me, if you don't believe it, you can check it yourself on the Internet, so if you have old books at home, don't throw them away or sell them casually, because it is likely that these things are very valuable treasures, of course, if you read this book, pass by the street used book stall again, and see the old books mentioned in my book, as long as the price is not high, just pick it up!