The United States is a country made up of many different races. Usually they are mixed together and can't be told from one another. But many of them still talk about where their ancestors came from. It is something they are proud of. The original Americans, of course were the Indians. The so-called white men who then came were mostly from England. But many came from other countries like Germany and France. One problem the United States has always had is discrimination. As new groups came to the United States they found they were discriminated against. First it was the Irish and Italians. Later it was the blacks. Almost every group has been able to finally escape this discrimination. The only immigrants who have not are the blacks. Surprisingly enough the worst discrimination today is shown towards the Indians. One reason the Indians are discriminated against is that they have tried so hard to keep their identity. Of course they are not the only ones who have done so. The Japanese have their Little Tokyo in Los Angeles and the Chinese a Chinatown in New York. The Dutch settlement in Pennsylvania also stays separate from other people. Their towns are like something from the 19th century. They have a different reason from the other groups for staying separately. They live separately for religious reasons rather than keep together in a racial group. Although some groups have kept themselves separate and others have been discriminated against, all groups have helped make the United States a great county. There is no group that has not helped in some way. And there is no group that can say they have done the most to make it a great country. Many people still come from other countries to help the United States grow. A good example is the American project that let a man walk on the moon. It was a scientist from Germany who was most responsible for doing that. It is certain that in the future the United States will still need the help of people from all racial groups to remain a great country.
单选题
Which of the following statements can best describe the main idea of this passage?