WASHINGTON (AP) – Decades from now, people will still be able to do “The Twist” and disco dancing thanks to the Library of Congress. It’s added “The Twist” and the “Saturday Night Fever” soundtrack to the National Recording Registry, which preserves sound recordings of cultural or historic importance. The Ramones’ 1976 self-titled album makes it as well. So does Pink Floyd’s “Dark Side of the Moon,” “Cheap Thrills” by Big Brother and the Holding Company, and Simon and Garfunkel’s “The Sounds of Silence.”