Break the law. Whether it is illegal or not depends on whether the postgraduate materials sold are authorized. It is illegal to sell the postgraduate entrance examination materials without authorization, which violates the copyright law and intellectual property law and needs to be investigated for criminal responsibility. Reselling refers to an economic activity in which units engaged in commercial activities play the role of middlemen, buying at low prices and selling at high prices, and earning profit at different prices. Under the condition of market economy, this is a normal phenomenon and the essence of most commercial activities. Whether it is illegal or not depends on whether the postgraduate materials sold are authorized. It is illegal to sell the postgraduate entrance examination materials without authorization, which violates the copyright law and intellectual property law and needs to be investigated for criminal responsibility. ? Whoever knowingly sells goods with counterfeit registered trademarks and the sales amount is relatively large shall be sentenced to fixed-term imprisonment of not more than three years or criminal detention and shall also, or shall only, be fined; If the sales amount is huge, he shall be sentenced to fixed-term imprisonment of not less than three years but not more than seven years and shall also be fined. If the circumstances are serious, he shall be sentenced to fixed-term imprisonment of not more than three years, criminal detention or public surveillance, and shall also be fined; If the circumstances are especially serious, he shall be sentenced to fixed-term imprisonment of not less than three years but not more than seven years and shall also be fined. For the purpose of making profits, anyone who commits any of the following cases of copyright infringement, with a relatively large amount of illegal income or other serious circumstances, shall be sentenced to fixed-term imprisonment of not more than three years or criminal detention, and shall also, or shall only, be fined; If the amount of illegal income is huge or there are other particularly serious circumstances, he shall be sentenced to fixed-term imprisonment of not less than three years but not more than seven years and shall also be fined:

Legal basis:1Chapter III of the Criminal Law revised in 997 "Crime of disrupting the order of the socialist market economy"

Section 7 Crimes of Infringement of Intellectual Property Rights Article 2 13? Whoever uses a trademark identical to its registered trademark on the same commodity without the permission of the owner of the registered trademark, if the circumstances are serious, shall be sentenced to fixed-term imprisonment of not more than three years or criminal detention and shall also, or shall only, be fined; If the circumstances are especially serious, he shall be sentenced to fixed-term imprisonment of not less than three years but not more than seven years and shall also be fined.