Hello! The incomplete plastic seal of books bought online may be due to logistics and the needs of sellers and buyers. You can think of it as an envelope or express outer packaging box. If the damage is severe enough to affect reading and storage, you can negotiate with the merchant through the purchasing platform for a return. In addition, according to Article 9 of the "Interim Measures for the Seven-Day Unreasonable Return of Goods Purchased Online" (revised in 2020), "If the goods are used beyond the inspection and confirmation of the quality and function of the goods, resulting in a significant depreciation of the value of the goods, the goods will be deemed to be defective. . The specific judgment criteria are as follows: (1) Food (including health food), cosmetics, medical equipment, and family planning supplies: the necessary disposable sealed packaging is damaged; (2) Electronic and electrical appliances: unauthorized repairs, modifications, and damage. , altering mandatory product certification marks, instruction labels, machine serial numbers, etc., leaving traces of appearance that are difficult to restore to their original state, or producing traces of data usage such as activation, authorization information, and unreasonable personal use data retention; (3) Clothing, shoes and hats, bags, toys, home textiles, and home furnishings: trademarks and logos were removed, and the goods were stained and damaged.”