单选题 The African (1) of today's black Americans were brought to the U.S. as slaves in the seventeen, eighteenth, and nineteenth centuries. They worked on farms, (2) on large farms in the southern states. (3) they became a part of the economic system of the South.
Slaves did not have the rights of people; (4) the law, they were "thing" which belonged to the person who bought them. They had to (5) the orders of their owners (6) . They were not allowed (7) to read; their owners feared that (8) slaves would begin to think about the (9) of the system and would learn to (10) their freedom. Slaves had to work long hours in (11) conditions Their owners had (12) power over them. They could be bought and sold like animals. At the slave markets, black children were separated form their parents and never saw them again. Slaves owners had the right to punish severely the slave who broke rules of (13) against the system. Slaves were often beaten (14) by their owners or killed. After the Civil War, one free slave (15) that his owner killed an old slave who was teaching him to read. There was a law against brutality to slaves, so (16) an owner who treated a slave badly could be punished. In practice, however, the law (17) nothing. Another law said that slaves could not give (18) white people, so very (19) owners were (20) punished for their brutality.