【推荐2】During the 1800s, African Americans worked long days in the fields of the American South. They sang songs that they had brought from Africa while working. One person sang a line. Then a group of workers repeated it. The songs' words told of the hardships             (艰苦) that people suffered. They clapped their hands and stomped (跺) their feet to the music.

In the 1860s, the music changed greatly. African American music took new forms. It was also influenced by dance music, which had great rhythm. Banjos (班卓琴) became popular. A blues singer usually sang a line and then played the banjo in reply. By the             early 1900s, the guitar had taken the place of the banjo in the blues music.

The blues music has many obvious characteristics. One of them is that the musical notes are often "bent". That is, they are changed slightly to give a song more strength.

Lyrics are the words of a song. Blues lyrics describe everyday life. The lyrics are often about the relationships between men and women. They tell about sadness and overwork. They tell about finding and losing love, having money or being poor, being             happy or sad and lonely. They almost always use the rhythms of everyday speech. A group of blues lyrics usually has three lines. The second line repeats the first line. The third line has different words.

By the 1940s, a large number of African Americans moved to Chicago. There, a new kind of "Chicago" blues began. The new music was excellent dance music. Chicago blues led to the birth of a new music style-rock and roll.

People use money to buy food, books, bicycles and hundreds of other things they need. When they work, they usually get paid in money.

Most of the money used today is made of metal(金属) or paper. But in ancient(古代的) time, people often used all kinds of things as money. One of the first kinds of money was shells(贝壳).

In China, cloth and knives were used as money. Elephant tusks(象牙), monkey tails and salt were used in some parts of Africa. Rice was also a kind of money used by the ancient people in some islands. Cows and other animals were used as money, too.

The first copper coins(铜币) were made in China.They were round and had a square(方形)hole in the center. Different countries had used different metal for their money. Later some countries began to make coins of gold and silver. But gold and silver were heavy to carry when people need a lot of coins to buy something expensive. The Chinese were the first to use paper money. The first paper money looked more like a note from one paper to another than the paper money used today.