Americans added a lot to the history of music between 1900 and 2000.Blues，rock and rap are all important musical developments.
    The blues is sad，slow music from America.Blues musicians are often African Americans.Blues songs often tell sad stories because Africans in America had difficult lives.
    Rock music comes from America too.It started in the 1950s.The slow，sad blues and American country music come together to make rock.It's good for dancing. Blues musicians usually play alone，but rock musicians usually play together.
    Rap music comes from African American music.It first started in the 1970s when young African Americans played on the streets of New York City.Many people now think that the words of rap music are really poems.Rap is very important in pop music.

（1）Why do Blue songs often tell sad stories？

Because Africans in America had difficult lives.

Because Africans in America had difficult lives.

（2）When did rock music start？

It started in the 1950s.

It started in the 1950s.

（3）Translate the underlined sentence.（翻譯劃線的句子）

藍調(diào)音樂家通常獨自演奏，但是搖滾音樂家通常一起演奏。

藍調(diào)音樂家通常獨自演奏，但是搖滾音樂家通常一起演奏。

（4）List the kinds of music according to the passage.（至少三種）

Blues，rock，rap.

Blues，rock，rap.

（5）Give a proper title to the passage.

The history of American music.

The history of American music.