听力原文： The African ancestors of today's black Americans were brought to the U. S. slave

s in the seventeenth，eighteenth, and nineteenth centuries．They worked on farms，especially the large farms in the southern states．Slowly they became a necessary part of the economic system of the South．

Slaves did not have the rights of people，according to the law, they were“things”which belonged to the person who bought them．They had to obey the orders of their owners without question． They were not allowed to learn to read, because their owners feared that educated slaves would begin to think about the injustice of the system and would learn to struggle for their freedom. Slaves had to work long hours in extremely unhealthy conditions．Their owners had complete power over them．They could be bought and sold like animals．At the slave markets, black children were separated from their parents and never saw them again． Slave owners had the right to punish severely any slave who broke rules or protested against the system. Slaves were often beaten brutally by their owners or killed． After the Civil War, one free slave reported that his owners killed an older slave who was teaching him to read. There was a law against brutality to slaves, so in theory an owner who treated a slave badly could be punished. In practice，however, the law meant nothing．Another law said that slaves could not give evidence against white people，so very few owners were ever punished for their brutality.

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A．They were too busy working to learn to read.

B．Their owners were afraid they could read.

C．They had no one to teach them to read.

D．They thought reading was not necessary.