这是一道主旨题，要求我们归纳文章的中心思想。速读全文后，我们就会发现D根本不是本文思想，应首先排除。B与原文的意思不符合。原文第三段第一句讲到美国一直有种族歧视问题，但没有说这是美国最严重的问题。A是本文第一段第一句的原话，但不足以概括全文的中心思想。而文章的第五段强调美国所有的种族都为建设美国做出了贡献，体现了文章的中心思想，所以C为正确答案。

　　（二）事实、细节题

　　这类问题要求考生找出例证、原因、时间和其它有关的细节或具体的数据等。细节题出题类型主要有以下几种：

　　1. According to the author， it is true that …

　　2. According to the passage， who （what， where， when）…… ？

　　3. How many （much）…… in this article？

　　4. In what way…… ？

　　5. In what year…… ？

　　6. What do we know about…… ？

　　7. Why is （are）…… ？

　　例如：

　　Fear and its companion pain are two of the most useful things that men and animals possess， if they are proper1y used. If fire did not hurt when it burnt， children would p1ay it until their hands were burnt away. Similarly， if pain existed but fear did not， a child would burn itself again and again， because fear would not warn it to keep away from the fire that had burn it before. A real1y fearless soldier —— and some do exist —— is not a good soldier because he is soon killed； and a dead soldier is of no use to his army. Fear and pain are therefore two guards without which men and animals might and die out.

　　In our first sentence we suggested that fear ought to be proper1y used. If， for example， you never go out of your house because of the danger of being knocked down and killed in the street by a car， you are letting fear rule you too much. Even in your house you are not absolutely safe： an airplane may crash on your house， or ants may eat away some of the beams in your roof so that the latter falls on you， or you may get cancer！

　　The important thing is not to let fear rule you， but instead to use fear as your servant and guide. Fear will warn you of dangers； then you have to decide what action to take.

　　In many cases， you can take quick and successful action to avoid the danger. For example， you see a car coming straight towards you； fear warns you， you jump out of the way， and all is well.

　　In some cases， however， you decide that there is nothing that you can do to avoid the danger. For examp1e， you cannot prevent an airplane crashing onto your house. In this case， fear has given you its warning； you have examined it and decided on your course， of action， so fear of this particular danger is no longer of any use to you， and you have to try to overcome it.

　　Question： Children wou1d p1ay with fire until their hands were burnt away if ______.

　　A. they were given no warning beforehand

　　B. they had never burnt themselves

　　C. they had no sense of pain

　　D. they were fearful of the fire

　　解答：选C.

　　本题是问文章中的一个细节。根据第一段的