单项选择题
You will hear three pieces of recorded material. Before listening to each one, you will have time to read the questions related to it. While listening, answer each question by choosing [A], [B], [C] or [D]. After listening, you will have time to check your answers. You will hear each piece once only. Questions are based on a brief review on American music. You now have 30 seconds to check your answers to Questions
Why did the black religious music became more joyful after the Civil War（）
A．The black achieved their personal freedom.
B．The piano was introduced into their band.
C．There were more and more performers in their band.
D．They had created a new musical tradition called jazz.