Why is the synchronous exercise book of the third grade (ninth grade) (first grade) of junior high school mathematics out of stock?
If it wasn't because all schools wanted to buy this kind of book, and then the students rushed to grab it, you would have lost it if you went late. It was because last semester was almost over ... The bookstore began to enter the next semester's books. In the first case, there will still be books, just wait for him to go shopping, and copy the homework first.