比如： 1）however，but ，nevertheless 等词预示着后面的内容与前面的不同或相反；
2） so…that…表示该句本身存在一种逻辑上的因果关系。 等等。
1. 定义（ definition）
通过上下文给出的定义，考生可以将某些生词的意思猜测出来。使定义与被定义的内容之间建立起关系的词有： put it in another way，mean，in other words，that is，or，namely等等。
从such as，like，for example，for instance，等词后所列举的例子以及所表示的前后同位关系可以猜测出一些单词的词意。
1） From this passage， we learn that…
2） The article was written to explain…
3） The author mainly discusses…
4） The best title for this passage is…。
5） The central idea conveyed in the above passage is…
6） The title that best expresses the main idea is…
7） What does the passage mainly discuss？
8） What is the main topic （theme， subject， point） of the passage？
9） What would be the most appropriate title for this passage？
10） Which of the following is the best title for this passage？
11） Which sentence best summarizes the article？
12） Which title suits this passage best？
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 racia1 group.
Although some groups have kept themselves separate and others have been discriminated against， al1 groups have helped make the United States a great country. 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 sti1l 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 wil1 still need the he1p of people from all racial groups to remain a great country.
Question： Which of the following statements can best describe the main idea of this passage？
A. The United States is a country made up of many different races.
B. Discrimination is the most serious problem in the United States.
C. All races in the United States have helped make the country a great one.
D. The prosperity of the United States is mainly due to the hard work of the most discriminated races.