听力原文： Today we are going to talk about copyrighting works of art. A copyright is a proof of authorship. It protects artists against someone else using their work without their permission. It's important to remember that United States Copyright Law protects artistic expressions such as paintings, but does not protect any ideas, concept, procedure' or technique. Under the United States Copyright Law, artists need to take several steps to obtain copyright protection. The law was changed in 1978 and again in 1989. For artists the current law means everything they create is automatically and immediately copyrighted. They don't have to file any documents and under the protection of the Copyright Law, any recreations of their original work such as prints are also covered by the artists' copyright. Furthermore, any changes artists made to their original works are covered. The law also makes it clear that when someone buys the work of art, they are not allowed to destroy or change that work of art. Artists keep the copyright even after selling the work of art. The purchaser may buy the physical work, but the right to make prints or copies is still the artists' and buyers does not automatically have any right to make and sell prints or copies of the work. Although works are automatically copyrighted, artists are encouraged to register their work with the United States Copyright Office. Registering art provides additional legal protection and also gives people around the world the ability to approach the owner about licensing and purchasing rights.(33)A．Protecting buyers of paintings.B．Why copies of famous paintings are made.C．How paintings are sold in the United States.D．Protecting artists from others' illegal use of their work.