听力原文：W: This evening, the guest speaker with us is Dr. Bush. (22)He's going to talk about copyrighting works of art. M: Well, a copyright is a proof of authorship. (22)It protects artists against someone else using their work without their permission. W: So, all artists' works will be protected by copyright law? M: It's important to remember that United States Copyright Law protects artistic expressions such as paintings, (23)but does not protect any ideas, concepts, procedures or techniques. W: How can artists obtain copyright protection? M: The law has changed in 1978 and again in 1989. (24)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 artist's copyright. Further more, any changes artists made to their original works are covered. The Law also makes it dear that when someone buys the work of art, they are not allowed to destroy or change that work of art. W: What if the work was sold to a new owner? M: (25)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 the buyer does not automatically have any right to make and sell prints or copies of work. W: Do you have any suggestions to our artists in this area? M: Although works are automatically copyrighted, artists are encouraged to register their work with United States Copyright Office. Registering art provides additional legal protection and also gives the people around the world the ability to approach the honors about licensing and purchasing right. (23)