Purchasing, specifically refers to helping mainland Chinese consumers to buy back goods from overseas. In recent years, the purchasing business has been booming in China with the help of e-commerce. Some people specialize in purchasing and the size of the purchasing market is expanding rapidly. The scale increased 19-fold between 2008 and 2012, reaching 48 billion yuan in 2012 and 74 billion yuan in 2013. In the past 6 years, about 60% of Chinese consumers who have purchased luxury goods have used purchasing. Therefore, a legal expert pointed out that as long as the purchaser pays the tariff, the purchase is not illegal; but if the purchaser pays the tariff, the price difference between the goods at home and abroad will be greatly reduced, the purchaser has no money to make, and the purchase is meaningless to them. According to the legal expert, which of the following can be derived? ['If purchasing is not illegal, purchasers must pay customs duties.', 'Purchasing is meaningful to them only if the purchaser does not pay tariffs.', 'In the past 6 years, most consumers who have used purchasing services have just purchased necessities.', 'In the past 6 years, most consumers who have used purchasing services have purchased luxury goods.']