单项选择题

At the end of the U. S. Civil War, about four million slaves were freed. Now, people around the world can
hear some of the former slaves’ stories for the first time ever, as told in their own voices.
"That was inslavery time, "says Charlie Smith in one interview. "They sold the colored people. And they were bringing them from Africa. They brought me from Africa. I was a child." The Library of Congress released the collection of recordings, Voices from the Days of Slavey, in January. The recorrdings were made between 1932 and 1975. Speaking at least 60 years after their emancipation(解放) ,the story teller discuss their experiences as slaves.
They also tell about their lives as free men and women.
Isom Moseley was just a boy at the time of emancipation, but he recalls that things were slow to change. "It was a year before the folks knowed they was free," he says.
Michael Taft, the head of the library’s archive of folk culture, says the recordings reveal something that written stores cannot. "The power of hearing someone speak is so much greater than reading someming from the page," Taft says. "It’s how something is said—the dialect, the low pitches, the pauses--that helps tell the Story.\
What do the storyteller tell us about