Read the text about the blues and choose the best answers. (6 pts)
Blues is a kind of slow sad music with strong rhythms. It was developed by African-American musicians in the American South. Early blues often took the form of a story about the unkind treatment experienced by African Americans. Many elements of the blues have grown from the music of Africa and religious music.
The blues started at the end of the 19th century and the first blues sheet music appeared at the beginning of the 20th century. Since then, it has developed into many styles such as country blues and urban blues. Several decades later. electric blues with electrical equipment replaced traditional blues. At the same time, the blues also reached a wider audience, especially white listeners. A mixture of blues styles and rock music, called blues rock appeared in the 60s and 70s of the last century.
㉞ What is the text mainly about?